Disk cartidge, disk recording medium device and disk recording and/or reproducing apparatus technical field

ABSTRACT

The present invention relates to a disk cartridge in which a disk-like recording medium such as an optical disk, a magneto-optical disk and a magnetic disk is accommodated within a disk compartment of a cartridge housing, a disk recording medium device in which the disk-like recording medium is accommodated in advance within the disk compartment so as to become freely rotatable and a disk recording and/or reproducing apparatus for recording and/or reproducing information by using this disk recording medium device. According to a disk cartridge of the present invention, there is provided a disk cartridge composed of a cartridge housing including an upper shell, a rotary member and a lower shell, a shutter member movable between the opening position and the closing position to open and close an opening portion of the cartridge housing and a shutter fixing means for holding the shutter member in the closed state at the closing position and in which the shutter member is held in the opened state at the opening position by the shutter fixing means. According to the present invention, there is no risk that vibrations generated from an external apparatus will be transmitted to the disk cartridge and the like through an open and hold mechanism. Thus, malfunctions caused by vibrations can be prevented or suppressed when information is written in and read out from the disk-like recording medium.

TECHNICAL FIELD

The present invention relates to a disk cartridge in which a disk-likerecording medium such as an optical disk, a magneto-optical disk and amagnetic disk is accommodated within a disk compartment of a cartridgehousing, a disk recording medium device in which the disk-like recordingmedium is accommodated within the disk compartment so as to becomefreely rotatable and a disk recording and/or reproducing apparatus forrecording and/or reproducing information by using this disk-likerecording medium.

BACKGROUND ART

As a disk recording medium device in which a disk-like recording mediumcapable of recording and/or reproducing information such as audio data,video data or computer data is accommodated within a cartridge housingso as to become freely rotatable, there is known a disk recording mediumdevice having an arrangement shown in FIG. 42, for example. This diskrecording medium device 1 is an information recording media whichincorporates therein a write once magneto-optical disk on which usersare able to record (write) information such as computer data later on.

This disk recording medium device 1 comprises a cartridge housing 2composed of a pair of upper shell 2 a and lower shell 2 b, amagneto-optical disk 4 accommodated within a disk compartment 3 of thiscartridge housing 2 so as to become freely rotatable and so forth. Thecartridge housing 2 has on its upper and lower surfaces provided anupper and lower opening portion 5 that extends from a central portion toone side. This opening portion 5 can be opened and closed by a shuttermember 6 that can slide along one side. The shutter member 6 isconstantly spring-biased in the direction to close the opening portion 5under spring force of a spring, not shown. Reference numeral 6 a denotesa presser member for preventing a tip end portion of the shutter member6 from being disengaged from the opening portion inadvertently.

The magneto-optical disk 4 has at its central portion provided adisk-like center hub 7 made of metal. This center hub 7 is located atthe position opposing to the inner end portion of the opening portion 5,i.e. located at substantially the central portion of the cartridgehousing 2. A turntable provided on the main body side of an informationrecording and reproducing apparatus is mounted to the center hub 7. Themagneto-optical disk 4 is chucked to the turntable and thereby themagneto-optical disk is rotated at a predetermined velocity (e.g.constant linear velocity). At that time, a magneto-optical pickup deviceof which the head portion is inserted into the opening portion 5functions to record or reproduce information on or from themagneto-optical disk 4.

However, in the conventional disk recording medium device having theabove-mentioned arrangement, the shutter member 6 that is provided onthe cartridge housing 2 so as to become freely slidable is constantlyspring-biased in the direction in which it closes the opening portion 3by a spring. When the disk recording medium device is in use, theshutter member 6 is slid in the direction in which it opens the openingportion 3 to open the opening portion against spring-biasing force ofthis spring. To this end, a disk recording and reproducing apparatusthat records and reproduces an information signal by using this diskrecording medium device 1 needs an open and hold mechanism for holdingthe shutter member 6 at the opening position in order to hold theopening portion 3 in the opened state while the disk recording mediumdevice is in use.

While such open and hold mechanism is generally provided on the diskrecording and reproducing apparatus, various vibration sources areexisting on the disk recording and reproducing apparatus and shocks areapplied to the disk recording and reproducing apparatus from the outsideunavoidably. Vibrations generated from this disk recording andreproducing apparatus or shocks inputted to the disk recording andreproducing apparatus from the outside are transmitted through the openand hold mechanism to the disk recording medium device 1. As a result,when vibrations from the disk recording and reproducing apparatus areapplied to the disk recording medium device 1, vibrations aretransmitted to the magneto-optical disk 4 and a magneto-optical head ofa magneto-optical pickup device and the like. There arises a problem inwhich an information signal is read out from and written in themagneto-optical disk 1 inaccurately.

When external shocks are applied to the disk recording medium device 1,it is unavoidable that the open and hold mechanism for holding theshutter member 6 at the opening position is disengaged from the diskrecording and reproducing apparatus. In such case, the shutter member 6that intends to move toward the closing direction is brought in contactwith the optical head of the optical pickup device and the turntable. Asa result, there is a risk that the optical head will be broken or thatthe shutter member 6 itself will be broken.

In particular, as a storage capacity of an optical disk is increasingprogressively and a recording density is increasing progressively,pitches of recording patterns is becoming narrower and linear density isincreasing more in recent years. Thus, when an information recordingsurface of a magnetic recording medium such as an optical disk and amagneto-optical disk is vibrated or smudged by dusts and the like, suchvibrations and the smudged information recording surface hinder theoptical pickup device from reading or writing information correctly. Sothat information cannot be read out from and written in the diskrecording medium device normally.

In view of the aforesaid aspect, it is an object of the presentinvention to provide a disk cartridge, a disk recording medium deviceand a disk recording and/or reproducing apparatus in which when ashutter member has finished opening the opening portion, pressure froman open and hold mechanism of an external apparatus and which is used tohold the shutter member at the opening position can be prevented frombeing applied to a cartridge housing so that the shutter member can beheld at the opening position by an inside mechanism.

DISCLOSURE OF THE INVENTION

In a disk cartridge according to the present invention, there isprovided a disk cartridge comprising a cartridge housing in which a diskcompartment is formed between an upper shell and a rotary member orbetween the rotary member and a lower shell by combining the uppershell, the rotary member and the lower shell, the rotary member issupported by at least one of the upper shell and the lower shell so asto become freely rotatable and an opening portion is formed on at leastone of the upper shell and the lower shell or at least one of the uppershell and the lower shell and the rotary member, a shutter memberprovided on the cartridge housing so as to become movable between theopening position at which it opens the opening portion and the closingposition at which it closes the opening portion in response to rotationof the rotary member, a shutter fixing means for holding the shuttermember in the closed state at the closing position and in which theshutter member is held in the opened state at the opening position bythe shutter fixing means.

Further, in a disk cartridge according to the present invention, thereis provided a disk cartridge comprising a cartridge housing in which adisk compartment is formed by combining an upper shell and a lower shelland an opening portion is provided on at least one of the upper shelland the lower shell, a shutter member provided on the cartridge housingso as to become movable between the opening position at which it opensthe opening portion and the closing position at which it closes theopening portion and a shutter fixing means for holding the shuttermember in the closed state at the closing position and in which theshutter member is held in the opened state at the opening position bythe shutter fixing means.

In a disk recording medium device according to the present invention,there is provided a disk recording medium device comprising a cartridgehousing in which a disk compartment is formed between an upper shell anda rotary member or between the rotary member and a lower shell bycombining the upper shell, the rotary member and the lower shell, therotary member is supported by at least one of the upper shell and thelower shell so as to become freely rotatable and an opening portion isprovided on at least one of the upper shell and the lower shell orbetween at least one of the upper shell and the lower shell and therotary member, a disk-like recording medium accommodated within the diskcompartment so as to become freely rotatable, a shutter member providedon the cartridge housing so as to become movable between the openingposition at which it opens the opening portion and the closing positionat which it closes the opening portion in response to rotation of therotary member and a shutter fixing means for holding the shutter memberin the closed state at the closing position and in which the shuttermember is held in the opened state at the opening position by theshutter fixing means.

Further, in a disk recording medium device according to the presentinvention, there is provided a disk recording medium device comprising acartridge housing in which a disk compartment is formed by combining anupper shell and a lower shell and an opening portion is provided on atleast one of the upper shell and the lower shell, a disk-like recordingmedium accommodated within the disk compartment so as to become freelyrotatable, a shutter member provided on the cartridge housing so as tobecome movable between the opening position at which it opens theopening portion and the closing position at which it closes the openingportion and a shutter fixing means for holding the shutter member in theclosed state at the closing position and in which the shutter member isheld in the opened state at the opening position by the shutter fixingmeans.

In a disk recording and/or reproducing apparatus according to thepresent invention, there is provided a disk recording and/or reproducingapparatus comprising a disk recording medium device including acartridge housing in which a disk-like recording medium is accommodatedwithin a disk compartment so as to become freely rotatable, a shuttermember movable between the opening position at which it opens an openingportion provided on the cartridge housing so as to expose a part of thedisk-like recording medium and the closing position at which it closesthe opening portion and a shutter fixing means for holding the shuttermember in the closed state at the closing position, a shutter openingand closing means for opening and closing the opening portion by movingthe shutter member in response to inserting and ejecting operations ofthe disk recording medium device and a table drive apparatus to whichthe disk recording medium device is loaded detachably and which isinserted into the disk recording and/or reproducing apparatus from theopening portion opened by the shutter opening and closing means to chuckand rotate the disk-like recording medium, wherein the cartridge housingis formed by combining the upper shell and the lower shell or bycombining the upper shell, the rotary member and the lower shell, thedisk compartment is formed between the upper shell and the lower shellor between the upper shell and the rotary member or between the rotarymember and the lower shell and the shutter member is held in the openedstate at the opening position by the shutter fixing means.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded perspective view showing a disk recording mediumdevice according to an embodiment of the present invention from theupper surface side in an exploded fashion.

FIG. 2 is an exploded perspective view showing a disk recording mediumdevice according to an embodiment of the present invention from thelower surface side in an exploded fashion.

FIG. 3 is a perspective view showing an upper shell of a disk cartridgefor use with a disk recording medium device according to the presentinvention from the upper surface side.

FIG. 4 is a bottom view of the upper shell of the disk cartridge for usewith the disk recording medium device according to the presentinvention.

FIG. 5 is a perspective view showing a chucking ring and a ring holderattached to the upper shell of the disk cartridge for use with the diskrecording medium device according to the present invention from theupper surface side.

FIG. 6 is a perspective view showing the central portions of thechucking ring and the ring holder attached to the upper shell of thedisk cartridge for use with the disk recording medium device accordingto the present invention from the lower surface side in across-sectional fashion.

FIG. 7 is a perspective view showing a rotary member of the diskcartridge for use with the disk recording medium device according to thepresent invention from the upper surface side.

FIG. 8 is a plan view of the rotary member of the disk cartridge for usewith the disk recording medium device according to the presentinvention.

FIG. 9 is a perspective view showing a pair of shutter members of thedisk cartridge for use with the disk recording medium device accordingto the present invention from the upper surface side.

FIG. 10 is a perspective view showing the assembled state of a pair ofshutter members of the disk cartridge for use with the disk recordingmedium device according to the present invention from the upper surfaceside.

FIG. 11 is a perspective view showing a lock member of the diskcartridge for use with the disk recording medium device according to thepresent invention from the upper surface side.

FIG. 12 is a perspective view showing the lock member of the diskcartridge for use with the disk recording medium device according to thepresent invention from the lower surface side.

FIG. 13 is a perspective view showing a mis-erase prevention member ofthe disk cartridge for use with the disk recording medium deviceaccording to the present invention from the upper surface side.

FIG. 14 is a perspective view showing the lower shell of the diskcartridge for use with the disk recording medium device according to thepresent invention from the upper surface side.

FIG. 15 is a plan view of the lower shell of the disk cartridge for usewith the disk recording medium device according to the presentinvention.

FIG. 16 is a perspective view showing the state in which a pair ofshutter members is attached to the rotary member of the disk recordingmedium device shown in FIG. 1 to thereby close the inside openingportion.

FIG. 17 is a perspective view showing an outward arrangement of the diskrecording medium device shown in FIG. 1.

FIG. 18 is a perspective view showing the disk recording medium deviceshown in FIG. 17 from the lower surface side and illustrates the statein which the opening portion is closed by closing a shutter mechanism.

FIG. 19 is a perspective view showing the disk recording medium deviceshown in FIG. 17 from the lower surface side and illustrates the statein which the opening portion is opened by opening the shutter mechanism.

FIG. 20 is an explanatory cross-sectional view taken along the linesconnecting a pair of positioning holes of the disk recording mediumdevice shown in FIG. 17.

FIG. 21 is an explanatory diagram view to which reference will be madein explaining chucking in the disk recording medium device according tothe present invention and illustrates, in a cross-sectional fashion, thestate obtained before an optical disk is attached to the turntable.

FIG. 22 is an explanatory diagram to which reference will be made inexplaining chucking in the disk recording medium device according to thepresent invention and illustrates, in a cross-sectional fashion, thestate obtained after the optical disk has been attached to theturntable.

FIGS. 23 are perspective views to which reference will be made inexplaining the manner in which the rotary member is elevated and loweredrelative to the upper shell when the opening portion of the diskrecording medium device according to the present invention is opened andclosed, wherein FIG. 23A is an exploded perspective view, FIG. 23B is aperspective view showing the state in which the rotary member is loweredrelative to the upper shell and FIG. 23C is a perspective view showingthe state in which the rotary member is elevated relative to the uppershell.

FIG. 24 is a diagram to which reference will be made in explaining howto calculate clearances among a cam portion of the upper shell and a camprotrusion of a rotary member of the disk cartridge according to thepresent invention and shows sizes of the upper shell, the rotary member,the lower shell and the shutter member in the form of referencenumerals.

FIG. 25 is a diagram to which reference will be made in explaining howto calculate a clearance between a cam portion of the upper shell and acam protrusion of a rotary member of the disk cartridge according to thepresent invention and shows its clearance in the form of referencenumerals.

FIG. 26 is a perspective view showing a disk recording and/orreproducing apparatus according to an embodiment of the presentinvention.

FIG. 27 is a perspective view showing a feed screw drive device of thedisk recording and/or reproducing apparatus according to the presentinvention and illustrates a part of a power transmission member and soforth in a cross-sectional fashion;

FIG. 28 is an explanatory block diagram showing a circuit arrangement ofa disk recording and/or reproducing apparatus according to an embodimentof the present invention.

FIG. 29 is a perspective view showing the state presented before thedisk recording medium device is loaded onto the table drive apparatus ofthe disk recording and/or reproducing apparatus according to the presentinvention.

FIG. 30 is a perspective view showing the state presented when the diskrecording medium device is being loaded onto the disk recording and/orreproducing apparatus according to the present invention.

FIG. 31 is a perspective view showing a shutter opening and closingmeans that opens and closes the shutter mechanism of the disk recordingmedium device according to the present invention.

FIG. 32 is a diagram to which reference will be made in explaining themanner in which the shutter mechanism of the disk recording mediumdevice according to the present invention is opened and closed by theshutter opening and closing means and illustrates the state obtaineduntil an initial operation convex portion of a rack rod reaches to anopening window of the lower shell after a pair of shutter members hadclosed the opening portion of the lower shell and the opening portion ofthe rotary member completely.

FIG. 33 is a plan view showing a main portion of FIG. 32 in anenlarged-scale.

FIG. 34 is a perspective view showing a main portion of FIG. 33 in amore enlarged-scale.

FIG. 35 is a diagram to which reference will be made in explaining themanner in which the shutter mechanism is opened and closed by theshutter opening and closing means in the state in which the lower shellis removed from the disk recording medium device according to thepresent invention and illustrates the state obtained when a pair ofshutter members is slightly opened (approximately 5°) after the initialoperation convex portion of the rack member had engaged with an initialoperation concave portion of the rotary member to enable the rotarymember begin to rotate.

FIG. 36 is a plan view showing a main portion in an enlarged-scale andto which reference will be made in explaining relationships among therotary member, the lower shell, the lock member and the like in thestate in which the upper shell is removed from the recording mediumdevice shown in FIG. 35.

FIG. 37 is a diagram to which reference will be made in explaining themanner in which the shutter mechanism is opened and closed by theshutter opening and closing means in the state in which the lower shellis removed from the disk recording medium device according to thepresent invention and illustrates the state obtained when a pair ofshutter members is largely opened (approximately 30°) after a rackportion of the rack rod had meshed with a gear portion of the rotarymember.

FIG. 38 is a plan view showing a main portion in an enlarged-scale andto which reference will be made in explaining relationships among therotary member, the lower shell, the lock member and the like in thestate in which the upper shell is removed from the disk recording mediumdevice shown in FIG. 37.

FIG. 39 is a diagram to which reference will be made in explaining themanner in which the shutter mechanism is opened and closed by theshutter opening and closing means in the state in which the lower shellis removed from the disk recording medium device according to thepresent invention and illustrates the state obtained when a pair ofshutter members opens the opening portion completely (approximately 55°)after a stopper convex portion of the rack member had engaged with a setposition concave portion of the rotary member.

FIG. 40 is a plan view showing a main portion in an enlarged-scale andto which reference will be made in explaining relationships among therotary member, the lower shell, the lock member and the like in thestate in which the upper shell is removed from the disk recording mediumdevice shown in FIG. 39.

FIG. 41 is an explanatory diagram showing a main portion and to whichreference will be made in explaining a tooth form of the rack portion ofthe rack rod shown in FIG. 31.

FIG. 42 is a perspective view showing a disk cartridge according to theprior art.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below withreference to the accompanying drawings. FIGS. 1 to 41 are diagramsshowing embodiments of a disk cartridge; a disk recording medium deviceand a disk recording and/or reproducing apparatus according to thepresent invention.

In the present application, “disk cartridge” refers to such a diskcartridge having a main arrangement comprising an upper shell, a lowershell or an upper shell, a lower shell and a rotary member and one or apair of shutter members (two shutter members and a combination of morethan three shutter members may be possible) and a housing presentedbefore a disk-like recording medium is accommodated. A “disk recordingmedium device” refers to such a disk recording medium device in which adisk-like recording medium is accommodated within a disk compartment andwhich comprises a combination of a cartridge housing and a disk-likerecording medium. Further, “disk recording and/or reproducing apparatus”refers to such a disk recording and/or reproducing apparatus whichcomprises a combination of a disk recording medium device, a table driveapparatus and the like.

A disk recording medium device 10 including a disk cartridge accordingto the present invention accommodates therein a read-only optical diskin which various information signals such as a music signal as audioinformation and a video signal and a music signal as video informationare recorded in advance or an optical disk in which information signalssuch as audio information and video information can be recorded onlyonce (write once optical disk) or an optical disk 11 in whichinformation signals such as audio information and video information canbe recorded repeatedly (rewritable optical disk) as a disk-likerecording medium.

However, the disk-like recording medium is not limited to theabove-mentioned optical disks and a magnetic disk having a magnetic thinfilm layer formed on the surface of a thin disk to store informationbased upon the magnetization state of the specific position, amagneto-optical disk capable of writing or reading information in or outof a similarly formed magnetic thin film layer by the use of an opticalhead and a magnetic head and other disk-like recording mediums can beapplied to the present invention, for example.

The disk recording medium device 10 comprises, as shown in FIGS. 1 and2, a cartridge housing 12 formed by combining a pair of an upper shell13, a rotary member 14 and a lower shell 15, an optical disk 11accommodated within a disk compartment 16 formed within this diskcartridge 12 so as to become freely rotatable, a pair of shutter members19 a, 19 b for opening and closing an inside opening portion 18 and anoutside opening portion 17 formed in the rotary member 14 and the lowershell 15 and the like. The disk cartridge is obtained by removing theoptical disk 11 from this disk recording medium device 10.

Since the disk recording medium device 10 generally uses the opticaldisk 11 such that the optical disk is placed in the horizontal state,the shell disposed on the upper side of the optical disk 11 is referredto as the “upper shell 13” and the shell disposed on the lower side ofthe optical disk 11 is referred to as the “lower shell 15”. However, thedisk recording medium device 10 is also able to use the optical disk 11such that the optical disk 11 is placed in the vertical state or in theoblique state. In such case, the upper shell 13 in this embodiment maybe referred to as a “first shell” and the lower shell 15 may be referredto as a “second shell”.

As shown in FIGS. 1 to 4, the upper shell 13 is formed of a thindish-like member having substantially a square shape of which the frontside is shaped like an arc. This upper shell 13 has a lower surface(surface appearing as a front surface in FIG. 4) in which an annularupper inner surface wall 21 continued in the circumferential directionis formed at the central portion thereof. A circular upper concaveportion 16 a is set on the inside of this upper inner surface wall 21.Then, an annular cam groove 22 is provided on the outside of the upperinner surface wall 21 so as to be continued in the circumferentialdirection to surround the upper inner surface wall 21. Cam portions 22 aof predetermined lengths (portions hatched in a cross-stripes fashion)are provided at three portions of the circumferential direction of thecam groove 22 with substantially an equal interval. The cam portion 22 ais adapted to lift up the rotary member 14 so that the rotary member mayapproach the lower shell 15 when the rotary member 14 is rotated,displaced and moved to a predetermined position of the upper shell 13.Actions of the cam portion 22 a will be described in detail later on.

On the outer peripheral edge of the upper shell 13, there are formed anupper front edge 13 a, left and right upper side surface edges 13 b, 13c and an upper rear surface edge 13 d. The upper front surface edge 13 ahas a first concave portion 23 a formed at its substantially centralportion to properly position the lower shell 15 and to insert and ejectan optical head which will be described later on. A central portion ofthe upper rear surface edge 13 d is concaved in the inside to provide aconcave portion 13 _(d0) to which the lower rear surface edge of thelower shell 15 is attached. Further, the upper rear surface edge 13 dhas a second concave portion 23 b formed at its substantially centralportion to properly position the lower shell 15. Then, the upper innersurface wall 21 has recesses 21 a, 21 b of shapes and sizescorresponding to the respective concave portions 23 a, 23 b formed atits positions opposing to the first and second concave portions 23 a, 23b.

Two front upper surrounding walls 24 a, 24 b are formed on one upperfront surface edge 13 a and between the upper side surface edge 13 c andthe cam groove 22 of the upper shell 13 with a predetermined clearance.Further, among the upper rear surface edge 13 d, the upper side surfaceedge 13 b and the cam groove 22, there are provided two rear uppersurrounding walls 24 c, 24 d with a predetermined clearance. Then, tworear side upper surrounding walls 24 e, 24 f are formed on the upperrear surface edge 13 d and between the upper side surface edge 13 c andthe cam groove 22 d with a predetermined clearance. These uppersurrounding walls 24 a to 24 f are set to be higher than the upper innersurface wall 21. In particular, the three upper surrounding walls 24 a,24 c and 24 e located at the respective corner portions are set to behigh enough to contact with the inner surface of the lower shell 15 uponassembly-process.

Further, on the inside of the rear upper surrounding wall 24 e of theupper shell 13, there is provided an upper concave portion 26 a of aplug housing portion 26 to which a mis-erase prevention member 25, whichwill be described later on, is attached slidably. This upper concaveportion 26 a is formed of the upper rear surface edge 13 d with an upperrecess 27 a for forming the upper half of the opening window 27 forsliding the mis-erase prevention member 25 and an upper housing wall 28a provided so as to surround the inside of the upper recess 27 a. Then,the upper concave portion 26 a is provided with a guide portion 29having two notches formed thereon to intermittently render the mis-eraseprevention member operative. Further, the upper shell 13 has screwfixing protrusions 30 formed at its four corner portions to fix thelower shell 15 by screws.

As shown in FIG. 3, the upper surface of the upper shell 13 is slightlyexpanded upwardly from the central portion to the rear surface, and anexpanded portion 31 of the upper shell has a nonskid holding concaveportion 31 a formed at its rear surface to prevent a user from slippingthe disk recording medium device when a user holds the disk recordingmedium device. This expanded portion 31 has a triangular instructionmark 31 b formed at its front surface to indicate the correct insertiondirection in which the disk recording medium device 10 should beinserted into the disk recording and reproducing apparatus. An uppersurface attachment surface 31 c is provided between the instruction mark31 b and the holding concave portion 31 a to attach a label where userscan write recorded contents and other necessary items.

A chucking ring 33 is supported at the central portion of the innersurface of this upper shell 13 by a ring holder 34 so as to becomefreely rotatable. The chucking ring 33 and the ring holder 34 havearrangements shown in FIGS. 5 and 6 in an enlarged-scale. Specifically,the chucking ring 33 is shaped like a disk made of a magnetic material(e.g. stainless steel SUS430, etc.) that can be attracted by a magnet.Then, a plurality of annular concave and convex portions havingdifferent diameters are provided at concentric circles, whereby thechucking ring 33 is provided with a flange portion 33 a located at theoutermost periphery of the concentric circle, a holding portion 33 bthat contacts with the optical disk 11, a tapered portion 33 c setbetween the holding portion 33 b and the flange portion 33 a, a positionrestriction portion 33 d located at the innermost periphery of theconcentric circle and an escape portion 33 e set between the positionrestriction portion 33 d and the holding portion 33 b.

The holding portion 33 b of the chucking ring 33 plays a role of apresser portion for pressing the optical disk against the turntable bypressing the peripheral edge portion that surrounds the center hole 11 aof the optical disk 11. This holding portion 33 b projects to onesurface side and the flange portion 33 projects to the opposite surfaceside. Then, with a proper step difference between the surface of theflange portion 33 a and the surface of the holding portion 33 b, theescape portion 33 e and the position restriction portion 33 d are setfrom the side of the holding portion 33 b to the flange portion 33 a.

The position restriction portion 33 d of the chucking ring 33 opposesthe tip end portion of the fitting portion 81 a of the turntable 81 asshown in FIGS. 21 and 22 and serves as a magnetic force receptionportion that receives magnetic force of a magnet 97 incorporated withinthe fitting portion 81 a. This position restriction portion 33 d isprovided at its center with a tapered concave portion 33 f matched withthe shape of the tip end portion of the fitting portion 81 a. Uponchucking, the tip end portion of the fitting portion 81 a is fitted intothe tapered concave portion so as to become freely detachable.

The ring holder 34 is generally shaped like a ring and includes aninward inside flange 34 a formed at one surface side and an outwardoutside flange 34 b formed on the other surface side. The ring holder 34supports the chucking ring 33 such that the chucking ring isaccommodated therein so as to become freely rotatable. The chucking ringhas the outside flange 34 b integrally fixed to substantially thecentral portion of the inner surface of the upper shell 13 by a fixingmeans such as fusion or adhesion using an adhesive agent. In order tomake the surface of the outside flange 34 b of the ring holder 34 becomeflush with the inner surface of the upper shell 13, the upper shell 13has an attachment hole 13 e into which the outside flange 34 b isfitted.

Although the inside diameter of the inside flange 34 a of this ringholder 34 is larger than the outside diameter of the holding portion 33b of the chucking ring 33, the inside diameter of the inside flange issmaller than the inside diameter of the flange portion 33 a and is largeenough to come in contact with the slanting surface of the taperedportion 33 c. Accordingly, the thick portion set on the inside of theradius portion of the chucking ring 33 is inserted into the center hole34 c of the ring holder 34 up to its intermediate portion. Then, thetapered portion 33 c of the chucking ring 33 is supported from theunderside by the inner peripheral edge of the inside flange 34 a of thering holder 34. As a consequence, within the ring holder 34, thechucking ring 33 can be moved in the plane direction in a predetermined,range and can also be moved in the thickness direction (axis direction)perpendicular to the plane direction within a predetermined range.

The attachment hole 13 e formed on the inner surface of the upper shell13 is provided with two annular convex portions 98 a, 98 b incorrespondence with the shape of the above-mentioned ring holder 34. Twoannular convex portions 99 a, 99 b are shaped so as to become concentricwith the center of the chucking ring 33. The outer surface of theposition restriction portion 33 d is opposed to the inner surface of thefirst annular convex portion 99 a set at the inside and the innersurface of the tapered portion 33 c of the chucking ring 33 is opposedto the outer surface of the second annular convex portion 99 b set atthe outside. According to the existence of the first and second annularconvex portions 99 a, 99 b, an inclination angle of the chucking ring 33can be decreased in the state in which the disk recording medium device10 is placed in the vertical direction.

The lower shell 15 is combined with the lower surface of the upper shell13. As shown in FIGS. 1, 2, 14 and 15, the lower shell 15 has theoutside shape approximately similar to that of the upper shell 13 and isformed of a thin dish-like member of approximately square-shape of whichthe front surface side is shaped like an arc. This lower shell 15 isprovided with the outside opening portion 17 that is opened in the frontsurface side. The outside opening portion 17 comprises a table openingportion 17 a provided at substantially the central portion of the lowershell 15 and a head opening portion 17 b extended from this tableopening portion 17 a along the radius direction and which is opened inthe front surface.

The outside opening portion 17 is adapted to enable a turntable of atable drive device, which will be described later on, and an opticalhead of an optical pickup device, which will be described later on, toface the optical disk 11 accommodated within the disk compartment 16.The outside opening portion is wide enough to enter and eject theturntable of the table drive apparatus and the optical head of theoptical pickup device. Specifically, the turntable is entered into andejected from the table opening portion 17 a and the optical head isentered into and ejected from the head opening portion 17 b.

Moreover, the lower shell 15 has lower inner surface walls 36 a, 36 b,36 c and 36 d of arc-shapes formed at its four corners, and the lowerconcave portion 16 b is set on the inside of the inner surface walls 36a to 36 d. Further, the outside opening portion 17 of the lower shell 15has a rib 37 formed at its inner surface peripheral edge to decrease aclearance between it and the shutter member for increasing an airtightproperty.

The rib 37 includes an arc-like rib portion 37 a formed along theperipheral edge of the table opening portion 17 a in a semicirclefashion, linear rib portions 37 b, 37 b formed along the two edges ofthe head opening portion 17 b in parallel to each other and symmetricalrib portions 37 c, 37 c extended in the opposite direction so as to wellbalance with the linear rib portions 37 b. The two linear rib portions37 b and the two symmetrical rib portions 37 c have shield portions 38a, 38 b formed at their outside portions to close clearances formed atthe outside portions of the two shutter members 19 a, 19 b.

Further, within the lower concave portion 16 b of the lower shell 15,there is provided a pair of operation convex portions 39 a, 39 b foropening and closing a pair of shutter members 19 a, 19 b based upon therotation movement of the rotary member 14. A pair of operation convexportions 39 a, 39 b is disposed at both sides of the outside openingportion 35 so as to sandwich the table opening portion 17 a.

The lower shell 15 has a lower front surface edge 15 a, right and leftlower side surface edges 15 b, 15 c and a lower rear surface edge 15 dformed at its outer peripheral edge. The lower front surface edge 15 a,the lower side surface edges 15 b, 15 c and the lower rear surface edge15 d have stepped structures in which stepped portions are formed on theintermediate portions of the height directions and in which the upperportions increase in thickness. The thin portions of the lower frontsurface edge 15 a, the right and left lower side surface edges 15 b, 15c and the lower rear surface edge 15 d enter the inside portions of theupper front surface edge 13 a, the upper side surface edges 13 b, 13 cand the upper rear surface edge 13 d of the upper shell 13 to cause therespective stepped portions to come in contact with the respective lowerend faces of the upper front surface edge 13 a, the upper side surfaceedges 13 b, 13 c and the upper rear surface edge 13 d.

An opening end 40 a of the head opening portion 17 b defined atsubstantially the central portion of the lower front surface edge 15 aof the lower shell 15 engages with the first concave portion 23 a of theupper shell 13 so that the front side is properly positioned. The lowerrear surface edge 15 d has a positioning portion 40 b (see FIG. 32)formed at its central portion to engage with the second concave portion23 b of the upper shell 13 so that the rear side is properly positioned.This positioning portion 40 b has a label attachment wall 41 provided atits outside and the outer surface of the label attachment wall serves asa label attachment surface. This label attachment wall 41 considerablyprojects toward the side of the upper shell 13 so as to become able tokeep a flat surface portion as wide as possible. Upon assembly-process,this label attachment wall is inserted into the concave portion 13_(d0).

The lower front surface edge 15 a, the lower side surface edge 15 c andthe inner surface wall 36 b of the lower shell 15 constitute a frontlower surrounding wall 42 a. Further, the lower rear surface edge 15 d,the lower side surface edge 15 b and the lower inner surface wall 36 cconstitute a rear lower surrounding wall 42 b. Then, the lower rearsurface edge 15 d, the lower side surface edge 15 c and the lower innersurface wall 36 d constitute a rear lower surrounding wall 42 c. As aresult, when the upper and lower shells 13, 15 are assembled, the frontupper surrounding wall 24 a of the upper shell 13 is fitted into theinside of the front lower surrounding wall 42 a. Then, the rear uppersurrounding wall 24 c is fitted into the inside of the rear lowersurrounding wall 42 b, and the rear upper surrounding wall 24 e isfitted into the inside of the rear lower surrounding wall 42 c.

Further, on the inside of the rear lower surrounding wall 42 c of thelower shell 15, there is provided the lower concave portion 26 b towhich the mis-erase prevention member 25 is attached. This lower concaveportion 26 b is composed of the lower rear surface edge 15 d in whichthe lower recess 27 b forming the lower half of the opening window 27 isformed and the lower housing wall 28 b provided so as to surround theinside of the lower recess 27 b. This lower concave portion 26 b has aguide groove 43 formed on its lower surface to guide the mis-eraseprevention member 25 to thereby restrict the slide direction. This lowerconcave portion 26 b and the upper concave portion 26 a constitute theplug housing portion 26.

This mis-erase prevention member 25 has an arrangement that is shown inFIG. 13 in an enlarged-scale. Specifically, the mis-erase preventionmember 25 is generally shaped like a cube and the front portion 25 a isprovided with a projection portion which projects to one side. Theopposite side of the projection portion of this front portion 25 isprovided with an operation protrusion 25 b that is used by users toslide the mis-erase prevention member 25. Further, the mis-eraseprevention member 25 has a guide protrusion 25 c formed on its lowersurface to slidably engage with the guide groove 43 of the lower shell15. The mis-erase prevention member has an engagement portion 25 dprovided on the rear surface opposite to the front surface portion 25 ato engage with the guide portion 29 to prevent the mis-erase preventionmember from being dropped. Although not shown, in the vicinity of thisengagement portion 25 d, there is provided a resilient member that isresiliently engaged with the recess of the guide portion 29, althoughnot shown. Resilience of this resilient member may enable users to feelsense of clicking when users slide the mis-erase prevention member.

Further, as shown in FIG. 15, the lower shell 15 has front attachmentholes 44 a and back attachment holes 44 b provided at four cornerportions to fasten the lower shell 15 to the upper shell 13 by screws.The respective rear attachment holes 44 b extend through cylindricalcylinder shaft portions 45 provided on the inner surface of the lowershell 15 and the tapping protrusions 30 of the upper shell 13 are fittedinto the inner surface side of the respective attachment holes 44 b.

Further, in the vicinity of the respective cylinder shaft portions 45,there are provided positioning shaft portions 46 a, 46 b. While thefirst positioning shaft portion 46 a is formed as a planar circle-likeconvex portion, the second positioning shaft portion 46 b is formed as aplanar oblong convex portion. The two positioning shaft portions 46 a,46 b have a pair of reference protrusions 47, 47 provided at their upperends to properly position the upper and lower shells 13, 15. A pair ofreference protrusions 47, 47 is circular in plane shape and isapproximately the same in height.

The upper shell 13 has a pair of reference holes 48, 48 corresponding toa pair of reference protrusions 47, 47 as shown in FIG. 20. In order toavoid interference with the respective reference protrusions 47, theupper shell 13 has an escape portion 49 a curved like a circle and anescape portion 49 b curved like an ellipse provided at the rear uppersurrounding wall 24 c and the rear upper surrounding wall 24 e as shownin FIG. 4.

The lower shell 15 has a pair of positioning holes 50 a, 50 b providedat its positioning shaft portions 46 a, 46 b to open in the lowersurface opposite to the reference protrusion 47. A pair of positioningholes 50 a, 50 b is adapted to properly position the disk recordingmedium device 10 at the disk loading portion that is the predeterminedposition of the disk recording and reproducing apparatus. To this end,while the first positioning hole 50 a is circular as seen from the flatsurface, the second positioning hole 50 b is shaped like an oblongellipse hole that can absorb size error generated in the horizontaldirection when the disk recording medium device is properly positionedto the disk loading portion.

The rotary member 14 is made freely rotatable within the upper and lowerconcave portions 16 a, 16 b formed when the upper shell 13 and the lowershell 15 having the above-mentioned arrangements are combined together.The upper and lower shells 13, 15 and the rotary member 14 constitutethe cartridge housing 12.

One side edge portions 13 b, 15 b of the upper and lower shells 13, 15thus combined have an opening window 52 formed at approximately theircentral portions to expose a part of the outer peripheral surface of therotary member 14. This opening window 52 consists of an upper recessportion 52 a provided at the joint portion of the upper shell 13 and alower recess portion 52 b provided at the joint portion of the lowershell 15. Further, the upper and lower shells 13, 15 have a loadingguide groove 53 provided at their one side edge portions 13 b, 15 b toextend along their joint surface in the front and rear direction. Theloading guide groove 53 is provided in order to enable a shutter openingand closing means, which will be described later on, to rotate therotary member 14 when the shutter opening and closing means is insertedinto the loading guide groove.

The other side edge portions 13 c, 15 c have a mis-insertion detectiongroove 54 extended in somewhere of the front and rear direction alongthe joint surface in an opposing relation to this loading guide groove53. Half portions of the loading guide groove 53 and the mis-insertiondetection groove 54 are provided on the upper shell 13 and the lowershell 15 so that square grooves are respectively formed when the twoshells 13, 15 are combined together. According to the combination of theloading guide groove 53 and the mis-insertion detection groove 54, thedisk recording medium device 10 can be prevented from being erroneouslyinserted into the apparatus when the disk recording medium device isloaded onto the table drive apparatus and hence the disk recordingmedium device 10 can constantly be loaded onto the table drive apparatuswith correct attitude.

Further, a lock housing portion 55 is formed on the inside of one frontedge portions 13 a, 15 a of the upper and lower shells 13, 15. Then, thelock housing portion 55 has a lock member 56, which shows a concreteexample of a shutter fixing means, swingably provided thereon to lockthe rotary member 14 at predetermined position. The lock housing portion55 is communicated with the lower concave portion 16 b and is alsocommunicated with the loading guide groove 53 through an opening hole 57bored on one side edge portions 13 b, 15 b. A support shaft 58 whichswingably supports the lock member 56 is provided on the lower shell 15forming one of the lock housing portion 55 in such a manner as toprotrude toward the side of the upper shell 13.

As shown in FIGS. 11 and 12 in an enlarged-scale, the lock member 56 isformed of a lever-like member that is fitted into the support shaft 58so as to become freely rotatable and which can swing in the planedirection. Specifically, the lock member 56 consists of an annularrotary shaft portion 56 a, an operation arm 56 b projecting to one sidefrom this rotary shaft portion 56 a and a lock arm 56 c and a resilientarm 56 d, both of which are projecting to the other side from the rotaryshaft portion 56 a. The operation arm 56 has an input portion 56 _(b1)provided at its tip end to project in the lateral direction. The inputportion 56 _(b1) of the operation arm 56 b has a hammerhead-like shapeand has strength large enough to endure pressing force applied from thelateral direction.

Pushing force is applied to the input portion 56 _(b1) of this operationarm 56 by a rack portion 85 a of a rack rod 95 which will be describedlater on. Specifically, when the disk recording medium device 10 isloaded onto the disk recording and/or reproducing apparatus, the gearteeth of the rack portion 95 a are brought in contact with the inputportion 56 _(b1) from the lateral direction due to relative movementbetween the disk recording medium device and the rack rod 95 so that theinput portion 56 _(b1) is pushed into the opening hole 57 by pressingforce of the gear teeth. Then, a plurality of gear teeth of the rackportion 95 a are sequentially brought in contact with the surfacesopposing the loading guide groove 53 of the input portion 56 _(b1),whereby the input portion 56 _(b1) is held within the opening hole 57.

A direction win which external force that is pushing force on thesurface in which each addendum of the rack portion 85 a comes in contactwith the input portion 56 _(b1) acts is set to be longer than anaddendum distance x of the rack portion 95 a that is the same as theaddendum distance x of the gear portion 60 a of the operated portion 60provided on the rotary member 14 so as to rotate the rotary member 14.As described above, when the length w of the input portion 56 _(b1) atits direction in which external force acts is set to be longer than theaddendum distance x of the rack portion 95 a, it is possible to preventthe disk cartridge from being broken when the disk cartridge is caughtwith addendums of the rack portion 95 a. A relationship between thelength w of this input portion 56 _(b1) and the addendum distance x ofthe rack portion 95 a will be described in detail with reference to FIG.41 later on.

The lock arm 56 c and the resilient arm 56 d of the lock member 56 havea clearance of a proper size formed therebetween. The resilient arm 56 dis given resilience of proper strength. Then, the lock arm 56 c has alock claw 56 _(c1) provided at its tip end and the resilient arm 56 dhas a support head portion 56 _(d1) provided at its tip end. The lockclaw 56 _(c1) of the lock arm 56 is formed of a wedge-like concaveportion that protrudes in the direction opposite to the input portion 56_(b1). This lock claw 56 _(c1) has a protrusion 56 _(c2) protruded fromits one side to the direction in which the hole of the rotary shaftportion 56 a is extended. A support head portion 56 _(d1) of theresilient arm 56 d is cylindrical in shape and this support head portion56 d1 is brought in contact with the lower front edge portion 15 a ofthe lower shell 15.

The lock member 56 having the above-mentioned arrangement is attached tothe support shaft 58 in the state shown in FIGS. 32 to 40. Specifically,in the state in which the lock claw 56 _(c1) is directed toward the sideof the lower concave portion 16 b, the rotary shaft portion 56 a isfitted into the support shaft 58 and the support head portion 56 d1 ofthe resilient arm 56 d is brought in contact with the inner surface ofthe lower front edge portion 15 a. As a consequence, the lock arm 56 cis inwardly spring-biased under spring force of the resilient arm 56 d,whereby the lock claw 56 _(c1) at the tip end of the lock arm isprotruded into the lower concave portion 16 b. At the same time, theinput portion 56 _(b1) of the operation arm 56 b is inserted into theopening hole 57 from the inside and the tip end of the input portion 56_(b1) is projected into the loading guide groove 53.

The lock member 56 that is the above-mentioned spring member may besuitably made of polyacetal (POM), for example. It is needless to saythat other engineering plastics can be applied to the lock member andthat a metal spring member can be used as the material of the lockmember. The lock member 56 is not limited to the shape of thisembodiment and shape, layout and so forth of the lock member can beselected properly so long as it includes the operation arm 56 b, thelock arm 56 c and the resilient arm 56 d. Conversely, the support shaft58 may be provided on the upper shell 13 so that it can be supported tothe side of the upper shell so as to become freely rotatable. Further,half support shafts may be protruded from both shells and two supportshafts may support the lock member 56.

The rotary member 14 that is made freely rotatable within the upper andlower concave portions 16 a, 16 b of the upper shell 13 and the lowershell 15 has the arrangement shown in FIGS. 1, 2, 7 and 8. This rotarymember 14 has a flat surface portion 14 a formed of a disk-like thinplate member and a ring portion 14 b continued to the outer peripheraledge of this flat surface portion 14 a. The inside opening portion 18 isformed on the flat surface portion 14 a of this rotary member 14. Thisinside opening portion 18 is substantially equal to the outside openingportion 17 of the lower shell 15 in shape and in size.

Specifically, similarly to the outside opening portion 17, the insideopening portion 18 also includes a table opening portion 18 a set at thecentral portion of the flat surface portion 14 a and into and from whichthe turntable is inserted and ejected and a head opening portion 18 bcontinued to the table opening portion 18 a and into and from which theoptical head is inserted and ejected. Then, the table opening portion 18a of the flat surface portion 14 a has the support edge portion 14 cprovided at its inner peripheral edge to support the insidenon-recording area of the optical disk 11 from the underside in the freecondition.

At one portion of the outer peripheral surface of the ring portion 14 bof the rotary member 14, there is provided an operated portion 60 thatis engaged with the rotary member by the shutter opening and closingmeans to rotate the rotary member 14 within a predetermined angularextent when the shutter opening and closing means is moved in areciprocation fashion. As shown in FIGS. 7, 8 and the like, thisoperated portion 60 includes a gear portion 60 a having a large numberof gear teeth formed over the circumferential direction in apredetermined angular extent (approximately 30°), a front slide portion60 b continued to one side of this gear portion 60 a, a rear slideportion 60 c continued to the other side of the gear portion 60 a, afirst land portion 60 d provided at the position distant from the gearportion 60 a in the circumferential direction by a predetermineddistance and a second land portion 60 e provided at the position distantfrom the front slide portion 60 b in the circumferential direction by apredetermined distance.

An inclined surface portion 60 f whose height on the side of the rearslide portion 60 c is decreased is provided between the rear slideportion 60 c and the first land portion 60 d of the operated portion 60.The outer peripheral surface of the front slide portion 60 b of theoperated portion 60 is substantially the same as the addendum circle ofthe gear portion 60 a in height, and the outer peripheral surface of therear slide portion 60 c is substantially the same as the bottom circleof the gear portion in height. Then, one side of the inclined surfaceportion 60 f is set to be substantially as high as the rear slideportion 60 c, and the other side is linearly extended like a tangent andis reached to the top surface of the first land portion 60 d. Further,the front slide portion 60 b has an initial operation concave portion 61a formed of a recess having an arc-like cross-section provided at itsapproximately central portion of the circumferential direction, and therear slide portion 60 c and the inclined surface portion 60 f have a setposition concave portion 61 b formed of a recess having a trapezoidalcross-section provided therebetween.

Since the gear portion 60 a and the front and rear slide portions 60 b,60 c of this operated portion 60 are protruded from the outer peripheralsurface of the ring portion 14 b to the outside, an upper escape portion52 a and a lower escape portion 52 b are provided on the correspondingportions of the upper shell 13 and the lower shell 15 so as to avoidthem from contacting with these protruded portions and to allow them topass therein as shown in FIGS. 4 and 15. The upper and lower escapeportions 52 a, 52 b constitute the opening window 52. Then, a secondengagement portion that is engaged by the lock claw 56 c, of the lockmember 56 is constructed at the position in which the opening portions17, 18 are closed by the set position concave portion 61 b.

The end portion on the opposite side of the gear portion 60 a of thefront slide portion 60 b comprises an end stopper 63 a of the openingside, the end portion on the opposite side of the inclined surfaceportion 60 f of the first land portion 60 d comprises a first endstopper 63 b of the closing side and the end portion opposing the endstopper 63 a of the second land portion 60 e comprises a second endstopper 63 a of the closing side. Then, the first end stopper 63 bcomprises a first engagement portion that is engaged by the lock claw 56c, of the lock member 56 at the opening position in which the openingportions 17, 18 are opened.

Thus, the lower shell 15, the rotary member 14 and the lock member 56are placed in the following positional relationship uponassembly-process. As shown in FIGS. 32 and 33, in the shutter closedstate in which the outside opening portion 17 of the lower shell 15 andthe inside opening portion 18 of the rotary member 14 are rotated anddisplaced most largely, the front slide portion 60 b of the operatedportion 60 is opposed to the opening window 52 of the cartridge housing12 and the first end stopper 63 b of the first land portion 60 d isbrought in contact with the opening end 40 a of the lower shell 15. Atthat time, the second end stopper 63 c of the second land portion 60 eis opposed to the positioning portion 40 b of the lower shell 15. Thelock claw 56 c, of the lock member 56 is engaged with the set positionconcave portion (second engagement portion) 61 b of the rotary member14, and the rotary member 14 is being locked by this lock member 56.

In this state, when the rotary member 14 is released from being lockedby the lock member 56 and is rotated in the predetermined direction by apredetermined angle, the inside opening portion 18 agrees with theoutside opening portion 17 and hence the two outside and inside openingportions 17, 18 are opened a great deal. As a result, the disk housingportion 16 is opened through the two outside and inside opening portions17, 18 to expose a part of the information recording surface of theoptical disk 11. At that time, the end stopper 63 a of the front slideportion 60 b contacts with the positioning portion 40 b of the lowershell 15 to prevent the rotary member 14 from being rotated more. Theset position concave portion 61 b is opposed to the opening window 52and the lock claw 56 c, of the lock member 56 is engaged with the firstend stopper 63 b, whereby the rotary member 14 is held in the lockedstate.

Arc-like cam protrusions 64 which are disposed at two places in thecircumferential direction are provided on the end face of the openingside of the ring portion 14 b of the rotary member 14. These camprotrusions 64 are engaged with the cam grooves of the upper shell 13when the rotary member 14 is assembled with the upper shell 13 and thelike. Then when the rotary member 14 is rotated a predetermined angle,the respective cam protrusions 64 are slid over the cam portions 22 a ofthe cam grooves 22, whereby the rotary member 14 is urged against theside of lower shell 15.

This rotary member 14 has a pair of support shafts 14 d, 14 d providedat its flat surface portion 14 a to support a pair of shutter members 19a, 19 a such that the shutter members can be freely rotated in the planedirection of the flat surface portion 14 a. A pair of support shafts 14d, 14 d forms supporting points corresponding to a pair of shuttermembers 19 a, 19 b and is disposed about the center of the table openingportion 18 a in a point symmetry fashion so that one of the supportshafts may be located at the edge portion of the head opening portion 18b.

A pair of shutter members 19 a, 19 b consisting the shutter mechanism 19attached to the rotary member 14 through a pair of support shafts 14 d,14 e is comprised of the two shutter members 19 a, 19 b which are thesame in shape and in size. A pair of shutter members 19 a, 19 b has ashape and a structure shown in FIGS. 9, 10 and so forth. Specifically, apair of shutter members 19 a, 19 b is formed of an approximatelysemicircular thin plate member.

Bearing holes 65 a are formed on the respective shutter members 19 a, 19b at their one side portions of the chord sides. A pair of supportshafts 14 d is engaged with the respective bearing holes 65 a so as tobecome freely rotatable, respectively. When the tip end portions of therespective support shafts 14 d are caulked, a pair of shutter members 19a, 19 b is placed over the flat surface portion 14 a of the rotarymember 14 and thereby attached so as to turn freely. At that time, apair of shutter members 19 a, 19 b is attached in such a manner thattheir chord sides may oppose to each other.

Stepped portions 66 having predetermined lengths in the directionperpendicular to the chord lines are provided on the chord sides of apair of shutter members 19 a, 19 b. The stepped portions 66 form aconvex-side joint portion 66 a and a concave-side joint portion 66 b attheir respective sides. The respective joint portions 66 a, 66 b haveoverhang portions 67 a, 67 b provided thereat so as to overhang in thedirections perpendicular to the directions in which the chords areextended. As a consequence, in a pair of shutter members 19 a, 19 b, theend face of the convex-side joint portion 66 a and the end face of theconcave-side joint portion 66 b are opposed to each other with theresult that the overhang portion 67 a of the convex-side joint portion66 a and the overhang portion 67 b of the concave-side joint portion 66b are fastened together.

As shown in FIG. 16, a pair of shutter members 19 a, 19 b is attached tothe rotary member 14 in such a manner that their chord sides may beopposed to each other. Accordingly, when a pair of shutter members 19 a,19 b is rotated so as to be detached from each other to the outside, therespective shutter members 19 a, 19 b are moved on the flat surfaceportion 14 a outwardly, by which the inside opening portion 18 is openedcompletely. On the other hand, a pair of shutter members 19 a, 19 b isrotated toward the inside to cause their joint portions 66 a, 66 b tocontact with each other, whereby the shutter mechanism 19 is shaped inapproximately circle. As a result, the central portion of the insideopening portion 18 is completely closed by a pair of shutter members 19a, 19 b.

Further, the respective shutter members 19 a, 19 b have open and closegrooves 68 provided thereon to allow the shutter members 19 a, 19 a toopen and close the opening portions 17, 18 through the rotation movementof the rotary member 14. One ends of the respective open and closegrooves 68 are set at substantially the central portions of therespective shutter members 19 a, 19 b and the respective open and closegrooves are formed so as to be extended to the outside of prolongedlines which connect one ends and the bearing holes 65 a. At the outsideend portions of a pair of open and close grooves 68, there are providedresilient members 69 a which are formed by recessing the above outsideend portions and concave portions 69 a which are used to escape theoperation convex portions 39 a, 39 b of the lower shell 15.Corresponding operation convex portions of a pair of operation convexportions 39 a, 39 b of the lower shell 15 are slidably engaged with apair of open and close grooves 68.

Furthermore, a pair of shutter members 19 a, 19 b has rib-escape grooves70 that are shaped like concave grooves corresponding to the ribs 37serving as the ribs of the lower shell 15 in the state in which theopening portions 17, 18 are closed completely. Specifically, therib-escape grooves 70 are formed like substantially U-shaped groovescorresponding to the arc-like rib portions 37 a and a pair of linear ribportions 37 b, 37 b of the ribs 37. On the opposite sides of therib-escape grooves, there are provided flat-surface-like escape surfaces70 a corresponding to the symmetrical rib portions 37 c, 37 c. Therib-escape grooves 70 and the ribs 37 constitute a labyrinth-likedust-proof clearance 71 having a crank-like shape as shown in FIG. 21.

This dust-proof clearance 71 has the above labyrinth-like clearance toprevent dusts and smudges from entering the disk compartment. Thedust-proof clearance 71 is formed when the rotary member 14 is rotatedin predetermined direction to allow a pair of shutter members 19 a, 19 bto completely close the opening portions 17, 18. The labyrinth-likeclearance having the crank-like shape is formed at the joint surfacebetween a pair of shutter members 19 a, 19 b and the lower shell 15,whereby dusts and smudges can be prevented from passing thereto withoutdifficulty. Thus, dusts and smudges can be prevented or effectivelysuppressed from entering the disk compartment 16.

Conversely, the above-mentioned ribs may be provided on a pair ofshutter members and corresponding rib-escape grooves may be provided onthe lower shell with similar effects being achieved. Although aclearance is set between the outer peripheral edge and the shuttermembers 19 a, 19 b on the side of the flat surface portion 14 a of therotary member 14, since such clearance is closed by a shielding portion38 a provided on the lower shell 15, it is possible to prevent dusts andsmudges from entering into the disk compartment from the aboveclearance.

A pair of shutter members 19 a, 19 b having the above-mentionedarrangement is assembled on the rotary member 14 with a predeterminedpositional relationship such that a pair of shutter members can open andclose the inside opening portion 18 as shown in FIG. 16. Then, therotary member 14 having a pair of shutter members 19 a, 19 b isassembled with a predetermined positional relationship relative to theupper and lower shells 13, 15 as shown in FIG. 20.

Specifically, when the cartridge housing 12 is assembled, the upper andlower shells are fastened together in such a manner that the insideopening portion 18 of the rotary member 14 may oppose to the outsideopening portion 17 of the lower shell 15. At that time, of the operatedportions 60 of the rotary member 14, the front slide portion 60 bcontinued to one side of the gear portion 60 a is disposed on theopening window 52 of the cartridge housing 12, whereby the initialoperation concave portion 61 a is disposed at substantially the centralportion of the opening window 52. This rotary member 14 and the uppershell 13 constitute the disk compartment 16 formed of a circular spaceportion.

This disk compartment 16 accommodates therein the optical disk 11, whichshows a concrete example of the disk-like recording medium, in such amanner that the optical disk can be freely rotated with predeterminedclearances in the outside of the radius direction and in the thicknessdirection. At that time, when the optical disk 11 is of the single siderecording system in which an information recording surface is formed ononly one side, the optical disk is accommodated within the diskcompartment in such a fashion that the information recording surfacethereof may be opposed to the opening portions 17, 18. As a result, alabel attachment surface, which is the other surface of the optical disk11, is set on the side of the upper shell 13 and the chucking ring 33 isopposed to the central center hole 11 a.

The optical disk 11 is formed of a thin disk-like recording memberhaving the center hole 11 a bored at its central portion. The turntable81 of the table drive apparatus 78 housed within the disk recording andreproducing apparatus is fitted into the center hole 11 a of the opticaldisk 11 as shown in FIG. 22. The chucking ring 33 is attracted bymagnetic force of the magnet 97 incorporated within this turntable 81and the optical disk 11 is held by the chucking ring 33 and theturntable 81 and thereby formed as one body in the rotation direction.Then, the turntable 81 and the optical disk 11 may be rotated togetherat a predetermined speed (e.g. constant linear velocity) by driving thespindle motor 75 to which the turntable 81 is attached.

Synthetic resins such as ABS resin (acrylonitrile-butadiene-styreneresin) and HIPS (high impact polystyrene resin), for example, may besuitable as materials of the upper shell 13, the rotary member 14, thelower shell 15, the shutter the members 19 a, 19 b, the mis-eraseprevention member 25 and the ring holder 34.

However, it is needless to say that other engineering plastics may alsobe used suitably and that other metal materials such as aluminum alloyand stainless steel can also be used suitably. A material of thechucking ring 33 is not limited to the above-mentioned stainless steel,and not only metals such as iron and other magnetic materials but alsomagnetic materials in which plastics have contained magnetic materialscan be applied to the material of the chucking ring.

The disk recording medium device 10 having the aforementionedarrangement can be assembled with ease as follows. The assembly work ofthis disk recording medium device 10 is carried out in the state inwhich the upper shell 13 is faced downward. First, the optical disk 11is set within the upper concave portion 16 a of the upper shell 13. Atthat time, the optical disk 11 is inserted into the upper concaveportion 16 a in the state in which the information recording surface isfaced downward.

Next, the opening side of the rotary member 14 is fitted into the upperconcave portion 16 a in such a manner as to cover the optical disk 11,whereby the optical disk 11 is rotatably accommodated within the diskcompartment 16 formed of the rotary member 14 and the upper shell 13. Atthat time, the direction in which the inside opening portion 18 of therotary member 14 is extended is made coincident with the front and reardirection of the upper shell 13 and the front slide portion 60 b of therat operated portion 60 is faced to the opening window 52.

It is desired that the shutter mechanism 19 should be assembled to therotary member 14 in advance. In that case, the chord sides of a pair ofshutter members 19 a, 19 b are opposed to each other, and the respectivebearing holes 65 a are fitted into the respective support shafts 14 d ofthe rotary member 14, thereby the shutter members being set on the flatsurface portion 14 a. Then, the tip end portions of the respectivesupport shafts 14 d are caulked to allow a pair of shutter members 19 a,19 b to be attached to the flat surface portion 14 a in such a mannerthat a pair of shutter members can open and close the inside openingportion 18.

Next, the lock member 56 is attached to the support shaft 58 of the lockhousing portion 55. At that time, the support head portion 56 _(d1) ofthe resilient arm 56 d of the lock member 56 is brought in contact withthe inner surface of the upper front edge portion 13 a of the uppershell 13 and the input portion 56 _(b1) of the operation arm 56 b isprotruded into the loading guide groove 53 from the opening hole 57 ofthe cartridge housing 12 under spring force of the resilient arm 56 d.Then, the lock claw 56 c, of the lock arm 56 c of the lock member 56 isengaged with the set position concave portion 61 b of the operatedportion 60. As a result, the rotary member 14 is locked by the lockmember 56.

At the same time or before and after the rotary member is locked by thelock member, the mis-erase prevention member 25 is attached to the plughousing portion 26. In this case, the mis-erase prevention member isinserted from the side of the guide protrusion 25 c, the engagementportion 25 d is engaged with the guide portion 29 and the operationprotrusion 25 b is engaged with the lower recess 27 b of the openingwindow 27.

Next, the lower shell 15 is laid over the rotary member 14 including theshutter mechanism 19 and this lower shell 15 is combined to the uppershell 13. At that time, the opening end 40 a of the lower shell 15 isfitted into the first concave portion 23 a of the upper shell 13, andthe positioning portion 40 b of the lower shell 15 is fitted into theconcave portion 23 b of the upper shell 13. At the same time, therespective positioning shaft portions 46 a, 46 b of the lower shell 15are fitted into the respective escape portions 49 a, 49 b of the uppershell 13. Then, the reference protrusions 47 provided on the respectivepositioning shaft portions 46 a, 46 b are fitted into the respectivereference holes 48 of the upper shell 13, whereby the lower shell 15 maybe properly positioned to the upper shell 13 automatically.

At that time, if a pair of shutter members 19 a, 19 b is set in thestate shown in FIG. 16, then a pair of operation convex portions 39 a,39 b provided within the lower concave portion 16 b of the lower shell15 can be respectively opposed to the concave portions 69 b of the openand close grooves 68 provided on the respective shutter members 19 a, 19b. As a result, regardless of the exact positions of a pair of open andclose grooves 68, a pair of operation convex portions 39 a, 39 b can beengaged with a pair of open and close grooves 68, 68 with ease only bycombining the lower shell 15 with the upper shell 13 together.

Thereafter, by the use of a plurality of stationary screws, the lowershell 15 can be fastened and fixed to the upper shell 13, whereby theassembly work of the disk recording medium device 10 having the outsideappearance and shape shown in FIG. 17 and which has the cross-sectionalarrangement shown in FIG. 20 is completed.

In this case, without using a fixing means consisting of separatemembers such as stationary screws, the joint surfaces of the upper shell13 and the lower shell 15 can be directly bonded together by a suitablemeans such as an adhesive agent. As described above, according to thedisk recording medium device 10 of this embodiment, the number of usedassemblies is relatively small and the assembly work can be carried outwith ease.

Although not shown, if the cartridge housing is provided with an openingportion of size corresponding to two of the above-mentioned openingportions 17, 18, then the disk recording medium device becomes able touse two optical heads simultaneously. In this case, the opening portionsof size corresponding to two opening portions may be disposed at a rightangle and thereby shaped as an L-like opening portion. Alternatively,the above-mentioned opening portions of size corresponding to twoopening portions may be disposed on a straight line in an opposingrelation to each other and thereby shaped as an I-like opening portion.

In this case, if the rotary member 14 and the lower shell 15 for usewith one head are used instead of the rotary member and the lower shellfor use with two heads, then while a new information signal is beingrecorded by one optical head, an information signal that has been justrecorded by the other optical head can be processed in such variousmanners as to confirm the recorded state of the information signal. Ifthe rotary members and the lower shells are exchanged with each otherfor one head or two heads, then the manufacturing process of the diskrecording medium device can cope with the manufacturing process for usein one head and the manufacturing process for use in two heads withease. Thus, the manufacturing and assembly lines can be made common andhence the disk recording medium device according to the presentinvention can properly meet the needs of users.

According to the disk recording medium device 10 having theaforementioned arrangement, the rotary member 14 can be rotated by smallforce, accordingly, a pair of shutter members 19 a, 19 b can be openedand closed by small drive force. In addition, the rotary member 14 cangenerate resistance to impacts and vibrations inputted from the outsideso that a pair of shutter members 19 a, 19 b may become difficult toopen.

The disk recording medium device 10 can be used by a disk recording andreproducing apparatus 73 which shows a concrete example of the diskrecording and/or reproducing apparatus having the arrangement shown inFIG. 26, for example.

The disk recording and reproducing apparatus 73 includes the tape driveapparatus 78 to chuck and rotate the optical disk 11 and the opticalpickup device 79 to read an information signal from the optical disk andto write an information signal on the optical disk by radiating laserbeams on the information recording surface of the optical disk 11 and ismounted on a chassis 74.

The chassis 74 is shaped like a flat surface having approximately asquare shape and includes a reinforcement rib 74 a that is obtained bycontinuously bending the peripheral edge of the chassis upward. Thereinforcement rib 74 includes support protrusions 74 b provided at itsfour positions to support the chassis 74 to the members on the side ofthe apparatus body shown in FIGS. 29 and 30.

A motor base plate 76 having the spindle motor 75 mounted thereon isfixed to approximately the central portion of the chassis 74 by a fixingmeans such as stationary screws. A first opening portion 77 a and asecond opening portion 77 b, both of which are shaped like squares, areprovided on the chassis 74 at its respective sides of the longitudinaldirections across the spindle motor 75. The table drive apparatus 78 isattached in association with the first opening portion 77 a. The secondopening portion 77 b is used to attach another table drive apparatus,not shown.

The disk recording and reproducing apparatus 73 consists of the tabledrive apparatus 78 for rotating the optical disk 11 at a predeterminedspeed (e.g. constant linear velocity), the optical pickup device 79which shows a concrete example of a pickup device for writing aninformation signal on the optical disk and for reading an informationsignal from the optical disk and a pickup movement apparatus 80 formoving this optical pickup device 79 close to or away from the tabledrive apparatus 78 and so forth.

The table drive apparatus 78 is comprised of the spindle motor 75, theturntable 81 integrally provided at the rotation portion of this spindlemotor 75 and the like. The spindle motor 75 is attached onto the motorbase plate 76 made of a thin plate metal, and a flexible wiring plate 76a is fixed to the upper surface of the motor base plate 76 by a fixingmeans such as an adhesive agent. Then, wiring of the spindle motor 75and wiring of a table drive connector are connected to the wiringcircuit of the flexible wiring plate 76 a. Further, a plurality offlexible wiring plates 76 b are fixed to the connector.

As shown in FIGS. 21, 22 and the like, the spindle motor 75 includes afixed portion 75 a fixed to the motor base plate 76 and a rotary portion75 b rotatably supported by this fixed portion 75 a. The turntable 81 isintegrally provided with a rotary shaft that serves as a rotation centerof the rotary portion 75 b. The turntable 81 includes a fitted portion81 a fitted into the center hole 11 a of the optical disk 11 and a tableportion 81 b disposed at the lower portion of this fitted portion 81 aand on which the peripheral edge portion of the center hole 11 a is heldand the like. Then, the fitted portion 81 a houses therein the magnet97. The chucking ring 33 is opposed to this turntable 81 and the opticaldisk 11 set on the table portion 81 b is held under attraction force ofthe chucking ring 33 attracted by the magnet 97, whereby the opticaldisk 11 can be chucked and rotated in unison with the turntable 81.

As shown in FIG. 26, a pair of guide shafts 82 a, 82 b is disposed inparallel to each other so as to sandwich the spindle motor 75 from bothsides. A pair of guide shafts 82 a, 82 b is formed of a round bar-likemember whose outer peripheral surface is made smooth. Then, the firstguide shaft 82 a is supported at its respective ends by an adjustmentplate 83. The second guide shaft 82 b is supported at its respectiveends by the chassis 74.

The adjustment plate 83 is attached to the chassis 74 in such a mannerthat its attitude can be changed. By changing the attitude of theadjustment plate 83, it becomes possible to adjust degree of parallelismbetween a pair of guide shafts 82 a and 82 b. By a pair of guide shafts82 a, 82 b, the optical pickup device 79 is supported so as to moveclose to or away from the turntable 81. One end portions of a pair ofguide shafts 82 a, 82 b are disposed at both sides of the spindle motor75 and the other end portions are made parallel to each other andextended in the direction in which they are moving away from the spindlemotor 75.

The optical pickup device 79 comprises a slide member 84 guided and slidby a pair of guide shafts 82 a, 82 b, an optical head set on this slidemember 84 and which can be moved back and forth in a reciprocationfashion and the like. The slide member 84 is large enough to cross apair of guide shafts 82 a, 82 b and is formed as a block-like shape inorder to increase rigidity. A pair of bearing portions 84 a is providedat one side of the longitudinal direction of this slide member 84 in thewidth direction crossing the longitudinal direction. The first guideshaft 82 a is slidably inserted into these bearing portions 84 a.Further, on the other side of the longitudinal direction of the slidemember 84, there is provided an insertion hole, not shown, into whichthe second guide shaft 82 b is inserted slidably. This insertion hole islarger than the diameter of the second guide shaft 82 b and hence theslide member 84 can be rotated about the first guide shaft 82 a so thatthe slide member can be inclined an amount corresponding to suchclearance in the upper and lower direction.

The optical head of the optical pickup device 79 includes a biaxialactuator having an objective lens 79 a, an optical control unit having asemiconductor laser, a photo-electric conversion element or the like forrecording and reproducing an information signal through this biaxialactuator and so forth. Most of the biaxial actuator is covered with ahead cover 79 b and the objective lens 79 a is exposed from an openingportion formed on this head cover 79 b. This objective lens 79 a isopposed to the information recording surface of the optical disk 11 setonto the turntable 81.

Of a pair of guide shafts 82 a, 82 b, the first guide shaft 82 a issupported by a pair of shaft support members 83 a, 83 a provided on theadjustment plate 83. The respective shaft support members 83 a areprovided with a pair of shaft presser plates 83 b and the first guideshaft 82 a is fixedly supported by fixing these shaft presser plateswith screws 83 c. The second guide shaft 82 b is supported by a pair ofshaft support members 74 c, 74 c provided on the chassis 74 and fixedlysupported by screwing with fixing screws 74 e. Then, a feed screw drivedevice 98 serving as a pickup movement device is attached to theadjustment plate 83.

The feed screw drive device 98 is comprised of a feed screw 85, a feedmotor 86, a support plate 87, a power transmission member 88 and thelike as shown in FIG. 27 in an enlarged-scale. The feed screw 85 isobtained by forming a streak of screw groove 85 a, which is spirallyextended, on an outer circumference surface of a round bar slightlyshorter than the guide shafts 82 a, 82 b along substantially the wholelength of the axis direction. A trapezoid shape whose cross-section istrapezoid having slight inclination angles on both side surfaces of thegroove may be suitable as the screw shape of this feed screw 85 and asquare thread whose cross-section forms a square may be suitable as theabove-mentioned screw shape of the feed screw. Moreover, a semicircularthread whose cross-section forms a semicircle may be applied to theabove-mentioned screw shape of the feed screw, and other screws ofwell-known shapes can be applied to the above-mentioned screw shape ofthe feed screw.

The feed screw 85 may serve as a rotary shaft of the feed motor 86,which is a drive source, as well. The feed screw is directly rotated bythe feed motor 86. The feed motor 86 includes a cylindrical motor case86 a and a case cover 86 b that closes one opening portion of the motorcase 86 a. The motor case 86 a is fixed to a motor supporting member 87a of a support plate 87 by a fixing means such as caulking and therebyconfigured integrally therewith. A coil portion that is wound in anannular fashion is fitted into and fixed to the inner peripheral surfaceof this motor case 86 a and an annular magnet is fitted into the insideof the coil portion by a fixing means such as insertion with pressure.

The support plate 87 is formed of a long and slender plate material madeof plate metal having approximately the same length as that of the feedscrew 85 a. The support plate 87 has a motor support member 87 a and ascrew support member 87 b provided at its respective ends in thelongitudinal direction, and the motor support member and the screwsupport member are opposed to each other when they are erected in thesame direction. The motor support member 87 a has an aperture 88 a boredat its central portion and has also a fitting aperture 88 b bored at itsheight position corresponding to the aperture 88 a in the upper portionof the screw support member 87 b. The feed motor 86 is fixed to theouter surface of the motor support member 87 a and the feed screw 85 isinserted into the aperture 88 a. Then, a tip end portion of the feedscrew 85 is supported by a bearing member, which is fitted into andfixed to the fitting aperture 88 b, so as to become freely rotatable.

The support plate 87 has a guide rib 87 c that is one side of thesupport plate obtained after one side of the width direction of thesupport plate has been continuously erected along the longitudinaldirection. This guide rib 87 c is disposed substantially just under thefeed screw 85 and is also extended in substantially parallel to the axisline of the feed screw 85. Further, the support plate 87 has twoinsertion apertures 87 d and two positioning apertures 87 e definedtherein. The two positioning apertures 87 e are used to properly locatethe support plate 87 at predetermined position, and the support plate isattached to the adjustment plate 83 by attachment screws 89 a insertedinto the insertion apertures 87 d.

A feed nut 90, which shows a concrete example of a power transmissionmember, is used to convert rotation force of the feed screw 85 intorectilinear motion and to transmit the rectilinear motion to the slidemember 84. The feed nut is composed of a first nut member 90 a and asecond nut member 90 b and a coil spring 90 c for spring-biasing the twonut members 90 a, 90 b in the direction in which they are moved awayfrom each other.

The first nut member 90 a includes a nut body shaped like a block and acylindrical cylinder shaft portion continued to one surface side of thisnut body and has also at its one side of the axial direction apertureextending through the nut body and the cylinder shaft portion a firstscrew portion 90 _(a1) that is screwed with the screw groove 85 a of thefeed screw 85. Further, the first nut member 90 a is provided with aprotrusion portion 90 _(a2) that is protruded in the lateral directionperpendicular to the axis direction. This protrusion portion 90 _(a2)has a slit extended in the direction in which the cylinder shaft portionis extended. The guide rib 87 c of the support plate 87 is engaged withthis slit so as to become freely slidable. The second nut member 90 b isformed of a sleeve-like cylindrical member and has an axis directionaperture bored at its central portion. The axis direction aperture has asecond screw portion 90 _(b1) formed at one side thereof to be screwedinto the screw groove 85 a of the feed screw 85. Further, the axisdirection aperture has a fitting aperture into which the cylindricalshaft portion of the first nut member 90 a is fitted detachably. Thisfitting aperture has a key-like protrusion that is protruded in theinside of the radius direction. The coil spring 90 c is interposedbetween the second nut member 90 b and the first nut member 90 a. Underspring force of this coil spring, a pair of nut members 90 a and 90 b isspring-biased in the direction in which the nut members are made distantfrom each other to thereby absorb axis-direction fluctuations generatedbetween the feed nut 90 and the feed screw 85.

The first and second nut members 90 a, 90 b having the above-mentionedarrangements and the coil spring 90 c are integrally combined andassembled on the feed screw 85. The assembly work of the first andsecond nut members and the coil spring will be described below, forexample. First, after the coil spring 90 c had been inserted into thecylinder shaft portion of the first nut member 90 a, the cylinder shaftportion is fitted into the fitting aperture of the cylinder shaftportion of the second nut member 90 b. Next, the feed screw 85 isinserted into the feed nut 90 where the two nut members 90 a, 90 b hadbeen assembled.

In this case, the coil spring 90 c is slightly contracted by moving thetwo nut members 90 a, 90 b close to each other. In the state in whichthis compressed state is being held, the feed screw 85 is turned andinserted into the feed nut 90. As a result, the thread portion of thefirst nut member 90 a is meshed with the screw groove 85 a of the feedscrew 85 and the thread portion of the second nut member 90 b issimultaneously meshed with the screw groove 85 a. As a result, underspring force of the coil spring 90 c, the first nut member 90 a isspring-biased in the direction in which it is moved away from the feedmotor 86, whereby the second nut member 90 b is spring-biased in thedirection in which it is moved close to the feed motor 86.

As a result, in the screw portion of the first nut member 90 a, thethread surface of the left-hand side shown in FIG. 27 is urged againstthe left-hand side thread surface of the feed screw 85 so that aclearance is produced between the right-hand side thread surface and theleft-hand side thread surface. Similarly, in the thread portion of thesecond nut portion 90 b, the thread surface of the right-hand side shownin the sheet of drawing is urged against the right-hand side threadsurface of the feed screw 85 so that a clearance is produced between theleft-hand side thread surface and the right-hand side thread surface. Asa result, a clearance on the whole of the feed nut 90 can be removed andhence fluctuations between the feed nut and the feed screw 85 can beabsorbed. Then, since the slit provided on the protruded portion 90_(a2) of the first nut member 90 a is engaged with the guide rib 87 c ofthe support plate 87, the feed nut 90 can be linearly moved to the axisdirection of the feed screw 85.

Further, the first nut member 90 a is provided with a drive protrusion90 d that protrudes in the lateral direction. This drive protrusion 90 dis engaged with a protrusion reception member 91 secured to the slidemember 84, and movement force of the feed unit 90 is transmitted throughthis protrusion reception member 91 to the slide member 84. Theprotrusion reception member 91 includes a fixing member 91 a for fixingthe protrusion reception member to the slide member 84, a support member91 b continued to this fixing member 91 a and a resilient member 91 ccontinued to the support member 91 b.

The fixing member 91 a is formed of a long and slender plate member andincludes the L-like support member 91 b provided at its one side of thewidth direction in somewhere of the longitudinal direction. Then, thesupport member 91 b includes a support portion 91 d formed of a recessprovided at its tip end corner portion of the free end side to receiveand support the drive protrusion 90 d. The resilient member 91 c hasresiliency of proper strength given by two corner portions formed of abent triangle, and a bent portion at the tip end is formed as a presserportion 91 e and opposed to the support portion 91 d. Further, thefixing member 91 a has a plurality of insertion apertures to attach theprotrusion reception member 91 to the slide member 84 and the protrusionreception member 91 is attached by a fixing means such as fixing screws.

The drive protrusion 90 d of the feed nut 90 attached to the feed screw80 is inserted into a clearance between the support portion 91 d of theprotrusion reception member 91 thus attached and the presser portion 91e. Then, the drive protrusion 90 d is held between the support portion91 d and the presser portion 91 e under spring force of the resilientmember 91 c, whereby force can be transmitted to the feed nut 90 and theslide member 84.

A stainless steel plate may be suitably used as materials of theadjustment plate 83 and the support plate 87, for example. It isneedless to say that a steel plate and other metal plates may also beused suitably as the materials of the adjustment plate and the supportplate and that engineering plastics having large strength may also beused suitably as the materials of the adjustment plate and the supportplate. Further, metal materials such as stainless steel that isdifficult to gather rust and which has sufficiently large strength maybe suitably used as a material of the feed screw 85. Furthermore, astainless steel plate having large strength may also be suitably used asa material of the protrusion reception member 91 and other platematerials also may be used as the material of the protrusion receptionmember.

The aforementioned pair of guide shafts 82 a, 82 b, the adjustment plate83 and the feed screw drive apparatus 98 constitute the pickup movementapparatus that an move the optical pickup device 79 close to or awayfrom the turntable 81. Next, a recording and reproducing apparatus body92 of the disk recording and reproducing apparatus 73 will be described.FIG. 28 shows a concrete example of the recording and reproducingapparatus body 92. The recording and reproducing apparatus body iscomprised of the following constituents. Specifically, the recording andreproducing apparatus body 92 includes three control apparatus of asystem controller S1, a memory controller S5 and a drive controller D1.

The system controller S1 and the memory controller S5 are directlyconnected and the connected line therebetween is connected to aread-only memory device (ROM) S2 and a random-access memory device (RAM)S3. Further, the memory controller S5 is connected with a memory S4, anencoder S6 for MPEG2 (moving picture compression system applied to theexisting television broadcasting that corresponds to 3M to 40 Mbps, HDTVand a broadband ISDN) and an MPEG2 decoder S7. Furthermore, the systemcontroller S1 is connected with a control panel S8 and a remote controlreception unit S9.

The drive controller D1 is connected with an error-correction processingcircuit (ECC) D4 and the connected line therebetween is connected with amemory device (ROM) D2, a memory device (RAM) D3, a servo circuit D6 andan address decoder D7. Further, the drive controller D1 is connectedwith a recording error judgment circuit D8 for judging whether or noterror occurs in the recording mode. This drive controller D1 isconnected through a command interface to the system controller S1.

The correction processing circuit D4 is connected through a datainterface to the memory controller S5 and is also connected to a modemcircuit D5. Then, the modem circuit D5 is connected to the optical headincluding the objective lens 79 a of the optical pickup device 79.Further, the servo circuit D6 is connected to the spindle motor 75, theoptical pickup device 79 and the recording error judgment circuit D8.Then, the optical pickup device 79 is connected to an address decoderD7, and the address decoder D7 is connected to the recording errorjudgment circuit D8.

The recording and reproducing apparatus body 92 having theabove-mentioned arrangement is accommodated within an armor case 93formed of a hollow housing shown in FIGS. 29 and 30, for example, and isused as a constituent of the disk recording and reproducing apparatus73. The armor case 93 includes a case body 93 a that is opened to theupper surface and the front surface, a case lid 93 b detachably attachedto the upper portion so as to close the upper surface of the case body93 a, a front panel 93 c detachably attached to the front portion so asto close the front surfaces of the case body 93 a and the case lid 93 band so forth. The disk recording and reproducing apparatus 73 includingthe recording and reproducing apparatus body 92, the above-mentionedtable drive apparatus 78 and so forth are accommodated within this armorcase 93.

The case body 93 a of the armor case 93, has leg members 93 d providedat its four portions to project downward. The front panel 93 c of thearmor case 93 is formed of an oblong plate member and has an oblongcartridge entrance and exit slot 94 provided at its upper portion. Thecartridge entrance and exit slot 94 has approximately the same size asthat of the front surface side of the disk recording medium device 10.This cartridge entrance and exit slot 94 is constantly closed by an openand close door 94 a disposed in its inside.

The open and close door 94 a is spring-biased in the closing side underspring force of a spring, not shown. As shown in FIG. 30, when the diskrecording medium device 10 is inserted into predetermined position bypressing the open and close door 94 a at the front portion of the diskrecording medium device, the disk recording medium device 10 can beautomatically loaded onto the disk recording and reproducing apparatusbody by a loading mechanism, not shown. Then, the disk recording mediumdevice 10 that has been transported by the loading mechanism is properlylocated at predetermined position within the armor case 93 and fixed. Atthe same time or before and after the disk recording medium device isproperly located and fixed, the shutter mechanism 19 of the diskrecording medium device 10 is opened by the shutter open and close meansprovided within the armor case 93, whereby the inside and outsideopening portions 17, 18 of the cartridge housing 12 are opened.

FIG. 31 shows a rack rod 95 that shows a concrete example of thisshutter open and close means. This rack rod 95 includes a rack portion95 a meshed with the gear portion 60 a of the operated portion 60 of therotary member 14, a front resilient member 95 b provided at the tip endside of this rack portion 95 a and a rear resilient member 95 c providedat the base end side of the same rack portion 95 a. The rack portion 95a of the rack rod 95 is formed of a straight rod material and isprotruded at its intermediate portion to one surface side. The rackportion has gear teeth the number of which is approximately the same asthat of the gear portion 60 a.

Assuming that the rack portion 95 a of the rack rod 95 is shaped asshown in FIG. 41, for example, then the distance x between adjacentaddendums of the rack portion 95 a and the length w of the input portion56 _(b1) of the lock member 56 should preferably have the followingrelationship.

Where m: module

-   -   α: pressure angle (e.g. 20°)    -   x: addendum distance    -   y: addendum size    -   h: height of tooth (h=m)    -   πm: pitch    -   πm/2: ½ of pitch

The pressure angle α is not limited to 20° and other angles such as14.5° can be applied to the pressure angle. The addendum size y is givenby the following equation: $\begin{matrix}{y = {{\pi\quad{m/2}} - {2\quad x\quad z}}} \\{= {{\pi\quad{m/2}} - {2\quad x\quad m\quad x\quad\tan\quad 20{^\circ}}}}\end{matrix}$

The addendum distance x is given by the following equation:$\begin{matrix}{x = {{\pi\quad m} - y}} \\{= {{\pi\quad m} - \left( {{\pi\quad{m/2}} - {2\quad x\quad m\quad x\quad\tan\quad 20{^\circ}}} \right)}} \\{= {{\pi\quad{m/2}} + {2\quad x\quad m\quad x\quad\tan\quad 20{^\circ}}}}\end{matrix}$

Therefore, the length w of the input portion 56 _(b1) is set to belarger than x (addendum distance). Such size relationship can be appliedto the rack portion 95 a of the rack rod 95 and the input portion 56 b,of the lock member 56 with the following effects being achieved, forexample.

When the shutter opening and closing operations of the disk cartridge ofthe above-described disk recording medium device 10 are carried out byrack-like parts integrally formed or composed of a plurality ofassemblies, the lock mechanism of the shutter mechanism is released bythe rack-like parts. At that case, when the length w of the inputportion 56 _(b1) for releasing the lock mechanism is set to be larger(longer) than the distance x between adjacent addendums of the rackportion 95 a, the addendum of the rack portion 95 a can constantly acton the input portion 56 _(b1). As a result, the input portion 56 _(b1)can be constantly pressed by the addendum of the rack portion 95 a, loadfluctuations generated such as when the input portion is caught with theaddendum of the rack portion 95 a can be suppressed so that smoothshutter opening and closing operations can be realized.

As a result, load fluctuations generated when the shutter of the diskrecording medium device 10 is opened and closed by the table driveapparatus 78 can be suppressed reliably without any special devices.Then, the input portion 56 _(b1) can be prevented from being caught withthe addendum of the rack portion 95 a of the rack rod 95 and the diskcartridge can be prevented from being broken when the input portion iscaught with the addendum.

The front resilient member 95 b of the rack rod 95 is extended in thesame direction of the rack rod 95 and is made resilient properly. Aninitial operation convex portion 96 a is provided at the tip end portionof the front resilient member. Further, the rear resilient member 95 cis similarly extended in the same direction of the rack rod 95 and ismade resilient properly. A stopper convex portion 96 b is provided atthe tip end portion of the rear resilient member. The initial operationconvex portion 96 a and the stopper convex portion 96 b are protruded inthe same direction as that of the gear teeth of the rack portion 95 aand these initial operation portion and stopper convex portion are seton the same straight line.

Further, although the initial operation convex portion 96 a has anarc-like cross-section, the size and height of the initial operationconvex portion are approximately the same as those of the gear teeth ofthe rack portion 95 a. On the other hand, although the stopper convexportion 96 b has a cross-section that is an angle form similarly to thegear teeth of the rack portion 95 a, the size and height of thecross-section of the stopper convex portion are formed slightly larger.Then, the front and rear resilient members 95 b, 95 c are givenresiliency of proper strength, whereby the initial operation convexportion 96 a and the stopper convex portion 96 b can be moved rearwardwith resiliency. In FIG. 31, reference numeral 95 d designates a guideportion that serves as a reinforcement portion for use with the rack rod95 as well. This guide portion 95 d is engaged with the loading guidegroove 53 of the disk recording medium device 10.

The manner in which the rotary member 14 of the disk recording mediumdevice 10 is rotated, the shutter mechanism 19 is opened and closed andother members are operated in unison with actions of the rack rod 95having the above-mentioned arrangement will be described with referenceto FIGS. 29 and 30 and FIGS. 32 to 40.

As shown in FIG. 29, the inside and outside opening portions 17, 18 ofthe disk recording medium device 10 are completely closed by the shuttermechanism 19 until the disk recording medium device is inserted into thecartridge entrance and exit slot 94 of the armor case 93. In this state,as shown in FIG. 30, when the disk recording medium device 10 isinserted from the cartridge entrance and exit slot 94 of the armor case93 into the disk recording and reproducing apparatus 73, the lock member56 is released from the locked state by the rack rod 95 disposed withinthe armor case 93. Thereafter, the rack rod 95 acts to open a pair ofshutter members 19 a, 19 b to allow the inside and outside openingportions 17, 18 to be opened, thereby a part of the informationrecording surface of the optical disk 11 being exposed.

First, as shown in FIGS. 30 and 32, when the disk recording mediumdevice 10 is inserted into the cartridge entrance and exit slot 94 ofthe armor case 93 a predetermined amount, the initial operation convexportion 96 a of the rack rod 95 is entered into the loading guide groove53 formed on one side surface portion of the disk recording mediumdevice 10. As a result, the initial operation convex portion 96 ainserts the input portion 56 _(b1) of the lock member 56 protruded inthe loading guide groove 53 into the lock housing portion 55 withpressure against spring-biasing force of the resilient arm 56 d.

Consequently, the lock member 56 is rotated about the support shaft 58to allow the lock claw 56, to be disengaged from the set positionconcave portion 61 b as shown in FIGS. 33 and 34. As a result, therotary member 14 is released from the locked state and thereby becomesable to rotate freely.

In this case, although the input portion 56 _(b1) that had been insertedinto the opening hole 57 with pressure by the initial operation convexportion 96 a is protruded into the loading guide groove 53 temporarilyunder spring force of the resilient arm 56 d, the input portion isinserted again into the opening hole 57 with pressure by the teeth ofthe rack portion 95 a continuing the initial operation convex portion 96a. The inserted state of this input portion 56 _(b1) is being continuedduring a period in which the rack portion 95 a is being opposed to theinput portion 56 _(b1). At that time, since the length w of the inputportion 56 _(b1) is larger than the distance x (=πm/2+2×m×tan 20°)between the adjacent addendums of the rack portion 95 a, the addendum ofthe rack portion 95 a can constantly act on the input portion 56 _(b1).As a result, hammering generated when the addendum of the rack portion95 a contacts with the input portion 56 b, and load fluctuationsgenerated when the input portion is caught with the addendum of the rackportion can be prevented or suppressed so that smooth shutter openingand closing operations can be realized.

Next, as shown in FIG. 35, the disk recording medium device 10 isinserted into the cartridge insertion direction F and the disk recordingmedium device 10 is advanced relative to the rack rod 95, whereby theinitial operation convex portion 96 a is brought in contact with thefront slide portion 60 b of the operated portion 60 of the rotary member14 and slid over the front slide portion 60 b. At that time, since thefront resilient member 95 b has resiliency of proper strength, when thefront resilient member 95 b is flexed, the initial operation concaveportion 96 a is flexed backward, moved and slid over the front slideportion 60 b. As a result, the initial operation convex portion 96 a isentered into the initial operation concave portion 61 a of the operatedportion 60.

This convex portion 96 a is engaged with the concave portion 61 a,whereby the rotary member 14 is rotated in the counter-clockwisedirection in the sheet of drawing by repulsive force from the rack rod95. As a result, the rotary member 14 is rotated a predetermined anglein response to a relative movement amount between it and the rack rod95, whereby the rack portion 95 a is meshed with the gear portion 60 aof the operated portion 60 before the convex portion 96 a is disengagedfrom the concave portion 61 a. Thus, a power transmission route becomesstrong so that movement force of the rack rod 94 is positivelytransmitted to the rotary member 14, thereby the rotary member beingrotated a predetermined angle. At that time, the lock claw 56, of thelock member 56 is moved upwardly along the inclined surface portion 60 eas shown in FIG. 36.

Next, as shown in FIG. 37, before the rack portion 95 a that linearlyadvances and the gear portion 60 a that advances in a curved fashion arereleased from being meshed with each other, the stopper convex portion96 b is engaged with the set position concave portion 61 b provided onthe rear slide portion 60 c of the operated portion 60. At that time,the lock claw 56 c, of the lock portion 56 is passed through theinclined surface portion 60 f and slid over the first land portion 60 das shown in FIG. 38.

Thereafter, as shown in FIG. 39, when the stopper convex portion 96 b isfirmly meshed with the set position concave portion 61 b, the rackportion 95 a and the gear portion 60 a are released from the meshedstate. Thus, the insertion operation of the disk recording medium device10 is completed and the disk recording medium device 10 is set to thecartridge loading portion that is the predetermined position of thetable drive apparatus 78.

At that time, the lock claw 56 _(c1) of the lock member 56 is slid alongthe top surface of the first land portion 60 d, dropped on the sidedistant from the gear portion 60 a and is thereby engaged with the firstend stopper 63 b as shown in FIG. 40. At the same time, the end stopper63 a of the front slide portion 60 b is brought in contact with thepositioning portion 40 b of the lower shell 15 from the inside. Theoperated portion 60 of the rotary member 14 is sandwiched by thepositioning portion 40 b and the lock claw 56 _(c1) from both sides andthe rotary member 14 is locked by the engagement of the lock claw 56_(c1) and thereby inhibited from being rotated. Thus, opening operationsof a pair of shutter members 19 a, 19 b are completed so that the insideand outside opening portions 17, 18 are opened completely.

Thereafter, pressing force applied to the cartridge housing 12 isreleased by the rack rod 95. Meaning for releasing the pressing force isto remove such a risk that vibrations and shocks generated on the sideof the table drive apparatus 78 when the rotary member 14 or the like isloosened by pushing force while pushing force is being applied to therotary member 14 and the like, for example, will be transmitted throughthe rack rod 95 to the cartridge housing 12. To be concrete, afteropening operations of a pair of shutter members 19 a, 19 b had beenfinished, the rack rod 95 is moved away from the cartridge housing 12and loads applied to the cartridge housing 12 (in particular, the rotarymember 14 and the like) are released by the rack rod 95.

At that time, the cartridge housing 12 of the disk recording mediumdevice 10 is positioned with high accuracy by a pair of reference holes48, 48 of the upper shell 13 and a pair of reference protrusions 47, 47of the lower shell 15 as described above, and a pair of positioningholes 50 a, 50 b are provided on the lower shell 15 so as to becomecoaxial with these reference protrusions 47 and so forth. Thus, when thedisk recording medium device 10 is loaded onto the disk loading portionof the table drive apparatus 78, since accuracy with which the lowershell 15 is positioned on the table drive apparatus 78 becomes equal toaccuracy with which the upper shell 13 is positioned on the table driveapparatus, it is possible to increase accuracy with which the uppershell 13 is positioned on the table drive apparatus.

In the state in which the disk recording medium device is set, since thestopper convex portion 96 b is firmly meshed with the set positionconcave portion 61 b, there is then no risk that the rotary member 14will be rotated. At that time, in the initial state in which the rotarymember 14 begins to rotate, as shown in FIGS. 23C and 25, a plurality ofcam protrusions 64 provided on the end face of the ring portion 14 b ofthe rotary member 14 are slid over the cam portion 22 a provided on thecam groove 22 of the upper shell 13.

As a result, the flat surface portion 14 a of the rotary member 14 ismoved toward the side of the lower shell 15, whereby a pair of shuttermembers 19 a, 19 b is held between the fiat surface portion 14 a and thelower shell 15. Thus, friction force is generated between the rotarymember 14 and the lower shell 15 so that force necessary for rotatingthe rotary member 14 should increase unavoidably. If the rotary member14 is rotated against friction force generated when the cam protrusionsare slid over the cam portion 22 a, then the cam protrusion 64 passesthe cam portion 22 a as shown in FIG. 23B. In consequence, sincefriction force generated when the cam protrusion 64 passes the camportion disappears, the rotary member 14 becomes able to rotate veryeasily and smoothly from now on.

A pair of shutter members 19 a, 19 a is rotated about the support shaft14 d in unison with the rotation of the rotary member 14. At the sametime, the operation convex portions 39 a, 39 b of the lower shell 15 areslidably engaged with the open and close grooves 68 provided on therespective shutter members 19 a, 19 b. Consequently, when the rotarymember 14 is rotated, the respective open and close grooves 68 arerotated relative to a pair of operation convex portions 39 a, 39 b. As aresult, a pair of shutter members 19 a, 19 b is moved toward the inside(toward the center of the rotary member 14) in which they are movedclose to each other in response to the rotation amount of the rotarymember 14.

Thus, a pair of shutter members 19 a, 19 b is changed from the stateshown in FIG. 32 through the states shown in FIGS. 35 and 37 to thestate shown in FIG. 39 to open the inside and outside opening portions17, 18 and thereby moved to the positions opposing in the right andleft. Thus, since the inside opening portion 18 of the rotary member 14and the outside opening portion 17 of the lower shell 15 are openedcompletely, a part of the optical disk accommodated within the diskcompartment 16 is exposed from the inside and outside opening portions17, 18 (see FIG. 19).

As a result, the inside and outside opening portions 17, 18 are changedfrom the state shown in FIG. 18 to the state shown in FIG. 19 with theresult that it becomes possible to insert the turntable 81 and theoptical head having the objective lens 79 a into the inside and outsideopening portions 17, 18. Accordingly, the turntable 81 or the like ismoved toward the side of the disk recording medium device 10 or the diskrecording medium device 10 is moved toward the side of the turntable 81and the state shown in FIG. 21 is changed into the state shown in FIG.22, whereby the turntable 81 is entered into the table opening portions17 a, 18 a provided at the central portion of the cartridge housing 12and the optical head is entered into the head opening portion 17 b, 18b.

Consequently, the fitting portion 81 a of the turntable 81 is fittedinto the center hole 11 a of the optical disk 11 and the peripheral edgeportion of the center hole 11 a is held on the table portion 81 b. Atthe same time, magnetic force from the magneto 97 incorporated withinthe fitting portion 81 a acts on the position restriction portion 33 dserving as the magnetic force reception portion of the chucking ring 33held on the ring holder 34 of the upper shell 13 and the chucking ring33 is attracted by the magnetic force. As a result, the holding portion33 b of the chucking ring 33 is urged against the peripheral edgeportion of the center hole 11 a of the optical disk 11 by the magneticforce of the magnet 97, whereby the peripheral edge portion is heldbetween the holding portion 33 b and the table portion 81 a of theturntable 81.

Consequently, the optical disk 11 is chucked onto the turntable 81 bythe chucking ring 33 and thereby the optical disk 11 is integrated withthe rotation direction of the turntable 81. At that time, the tip endportion of the table portion 81 a of the turntable 81 is fitted into theconcave portion 33 f of the position restriction portion 33 d of thechucking ring 33, whereby the chucking ring 33 is properly positioned tothe turntable 81 at the same time. Thus, the chucking ring 33 isproperly positioned at substantially the central portion of theturntable 81.

As a result, the chucking ring 33 is floated from the upper shell 13 sothat predetermined clearances are held between the inner surface of thetapered portion 33 c of the chucking ring 33 and the outside inclinedsurface of the second annular convex portion 99 b of the upper shell 13,between the outer surface of the tapered portion 33 c and the innerperipheral edge of the inner flange 34 a of the ring holder 34 andbetween the surface of the position restriction portion 33 d of thechucking ring 33 and the inside inclined surface of the first annularconvex portion 99 a of the upper shell 13 to thereby prevent theabove-mentioned elements from rubbing with each other.

Concurrently with the chucking operation, the optical head of theoptical pickup device 79 enters into the opening portions 17, 18 toallow its objective lens 79 a to oppose the information recordingsurface of the optical disk 11 with a predetermined clearance. Thus, thedisk recording and reproducing apparatus 73 becomes able to reproduce orrecord an information signal from or on the information recordingsurface of the optical disk 11.

Accordingly, the table drive apparatus 78 is operated, the spindle motor75 is driven to rotate the optical disk 11 through the turntable 81. Atthe same time, the optical pickup device 79 is driven to allow theobjective lens 79 a of the optical head to irradiate laser beams on theinformation recording surface of the optical disk 11. Thus, theinformation signal can be read out from the information recordingsurface of the optical disk 11 or a new information signal can bewritten on the information recording surface. In this manner, theinformation signal can be reproduced or recorded by the disk recordingand reproducing apparatus 73.

Next, the manner in which the disk recording medium device 10 is ejectedfrom the armor case 93 will be described. After the information signalhad been reproduced or recorded, when a user operates a cartridge ejectbutton (not shown) provided on the armor case 93, for example, theloading mechanism is activated to disengage the disk recording mediumdevice 10 from the disk recording and reproducing apparatus 73 so thatthe disk recording medium device is ejected from the armor case 93.

For example, in the state in which the disk recording medium device 10is fixed to the disk loading portion, the spindle motor 75 is movedrearward and the turntable 81 is pulled out from the opening portions17, 18 of the disk recording medium device 10. At that time, when thespindle motor 75 is moved rearward, first, the turntable 81, the opticaldisk 11 and the chucking ring 33 are moved in unison with each other.Then, when the turntable, the optical disk and the chucking ring aremoved a little in unison with each other, the tapered portion 33 c ofthe chucking ring 33 is brought in contact with the inner peripheraledge of the inner flange 34 a of the ring holder 34 fixed to the uppershell 13.

When the spindle motor 75 is further moved rearward, the movement forceof the spindle motor becomes larger than the attraction force of themagnet 97 so that the chucking ring 33 is detached from the turntable byresistance of the ring holder 34. As a result, the chucking ring 33 isheld on the upper shell 13 by the ring holder 34. Next, the peripheraledge portion of the center hole 11 a of the optical disk 11 is broughtin contact with the support edge portion 14 c of the rotary member 14and the spindle motor 75 is further moved rearward to allow the fittingportion 81 a of the turntable 81 to be removed from the center hole 11 aof the optical disk 11. As a result, the optical disk 11 is held withinthe disk compartment 16 of the cartridge housing 12. Then, the spindlemotor 75 is continuously moved rearward until the turntable 81 iscompletely extracted from the opening portions 17, 18.

Thereafter, when the disk recording medium device 10 is moved in theeject direction by eject operation of the loading mechanism, the rackrod 95 is relatively move rearward. When the disk recording mediumdevice 10 is moved rearward relative to this rack rod 95, the rotarymember 14 is rotated by the stopper convex portion 96 b engaged with theset position concave portion 61 b. Then, before the convex portion 96 bis disengaged from the concave portion 61 b, the rack portion 95 a ismeshed with the gear portion 60 a and the rotary member 14 is continuedto rotate by the meshed state between the rack portion and the gearportion.

At that time, since the tip end of the stopper convex portion 96 b ofthe rack rod 95 has already been inserted into the opening window 52 ofthe cartridge housing 12, the convex portion 96 b is brought in contactwith the edge of the opening window 52. However, since the rearresilient member 95 c that was integrated with the convex portion 96 bhas resiliency of proper strength, this rear resilient member 95 c isflexed and deformed with the result that the convex portion 96 b isdeformed to the outside with resiliency and passed through the edge ofthe opening window 52. Therefore, even though the height of the convexportion 96 b is higher than the height of the gear teeth of the rackportion 95 a, the convex portion 96 b distant from the concave portion61 b can be easily extracted from the opening window 52. Accordingly,the rotation of the rotary member 14 will be maintained later on.

When the rotary member 14 is rotated, the initial operation convexportion 96 a is engaged with the initial operation concave portion 61 abefore the rack portion 95 a is disengaged from the gear portion 60 awithin the opening window 52. The convex portion 96 a is engaged withthe concave portion 61 a, whereby the rotary member 14 is continued torotate and the rotary member 14 is rotated to the initial position. As aresult, since the second end stopper 63 c of the rear slide portion 60 cof the operated portion 60 is brought in contact with the positioningportion 40 b of the lower shell 15, this contact will hinder the rotarymember 14 from rotating later on.

On the other hand, since the disk recording medium device 10 and therack rod 95 are continued to move relatively, the rotary member 14 isgiven rotation force by movement force of the convex portion 96 aengaged with the concave portion 61 a. Repulsive force of this rotationforce is given to the convex portion 96 a, the front resilient member 95b is flexed and deformed by this repulsive force and the convex portion96 a is moved to the outside, thereby the engagement between the convexportion and the concave portion 61 a being released.

Thereafter, the initial operation convex portion 96 a of the rack rod 95is passed through the opening hole 52, whereby the input portion 56_(b1) of the lock member 56 is protruded from the opening hole 57 intothe loading guide groove 53. At the same time, the lock claw 56 _(c1) ofthe lock member 56 is moved to the inside and thereby meshed with theset position concave portion 61 b of the operated portion 60 of therotary member 14. As a result, the lock member 56 locks the rotarymember 14 to stop rotation of the rotary member.

At that time, a pair of shutter members 19 a, 19 b executes operationsopposite to those executed when the disk recording medium device isinserted into the armor case to thereby close the inside and outsideopening portions 17, 18 completely. Since the cam protrusion 64 of therotary member 14 is located within the cam groove 22, the rotary member14 can be rotated by small force. Further, since the cam protrusion 64is brought in contact with the cam portion 22 a and slid over the camportion, the above-mentioned friction force will be applied to rotationof the rotary member 14 later on. Then, immediately before the shuttermechanism 19 is closed, the operation convex portion 39 b (or 39 a)moves the open and close groove 68 to the outermost side portion so thatthe operation convex portion contacts with and presses the resilientmember 69 a. Thus, spring force is generated in the resilient member 69a by pushing force of the operation convex portion 39 b (or 39 a)

Under spring force of this resilient member 69 a, urging force foracting on the other shutter member 19 a (or 19 b) is generated in thecentral stepped portion. Since this urging force is produced in both ofthe shutter members 19 a, 19 b, an airtight property of a pair ofshutter members 19 a, 19 b can be improved more by their urging force.Therefore, a dust-proof property at the joint portion between a pair ofshutter members 19 a and 19 b can be improved so that dusts and smudgescan be prevented from entering the disk compartment 16 more effectively.

In this manner, the whole of the inside and outside opening portions 17,18 is completely closed by a pair of shutter members 19 a, 19 b (seeFIG. 32, etc.), and in this closed state, the disk recording mediumdevice 10 is ejected from the cartridge entrance and exit slot 94 of thearmor case 93 to the outside of the case. Thus, the ejection operationof the disk recording medium device 10 is completed.

In the above-mentioned disk recording medium device 10, the sizes of thethickness direction among the upper shell 13, the rotary member 14, thelower shell 15 and the shutter members 19 a, 19 b should preferably beset so as to satisfy the relationships shown in FIGS. 24 and 25 and anequation. Meanings of reference letters A to K shown in FIG. 24 andreference symbol Σ shown in FIG. 25 are as follows:

(1) A: height from the end face of an upper front surface edge 13 a ofthe upper shell 13 or the like to the surface of the cam groove 22A=2.9 mm+0.1/0 mm

(2) B: height from the end face of the upper front surface edge 13 a ofthe upper shell 13 or the like to the upper surfaceB=3.85 mm±0.05 mm (reference size)

(3) C: height from the end face of the lower front surface edge 15 a ofthe lower shell 15 or the like to the lower surfaceC=4.15 mm+0.1/−0 mm (reference size)

(4) D: height from the end face of the lower front surface edge 15 a ofthe lower shell 15 or the like to the bottom surfaceD=3.3 mm±0.05 mm

(5) E: thickness of the shutter members 19 a, 19 bE=1.1 mm+0/−0.05 mm

(6) F: height from the lower surface of the rotary member 14 to the endfaceF=4.7 mm+0/−0.1 mm

(7) G: height of the cam protrusion 64 of the rotary member 14G=0.2 mm+0/−0.05 mm

(8) H: height of the cam portion 22 a of the upper shell 13H=0.2 mm+0/−0.05 mm

(9) J: height of the rib 37 of the lower shell 15J=0.2 mm+0/−0.05 mm (reference size)

(10) K: depth of the rib escape groove 70 of the shutter members 19 a,19 bK=0.2 mm+0.05/−0 mm (reference size)

(11) Σ: ideal clearance produced between the cam portion 22 a and thecam protrusion 64 upon assembly-process

Σ=−H+A+D−E−F−G . . . *=0 mm+0.45/−0 mm (accumulated tolerance) 0.064mm+0.322/−0 mm (mean square×1.66)

As is clear from the above-mentioned equation *, the ideal clearance Σshould preferably be selected in a range of from 0 mm to 0.45 mm and themost preferable value of the ideal clearance is approximately 0.2 mm.

In this embodiment, the rotary member 14 that rotates to open and closethe shutters may be operated in a clearance of approximately 0.4 mm(center value of tolerance) between the upper shell 13 and the lowershell 15. The clearance is narrowed to approximately 0.2 mm when thedisk recording medium device is preserved. When the clearance rangingfrom 0 mm to 0.45 mm (optimum value is about 0.2 mm) is set while therotary member 14 is not urged against the upper shell 13 as describedabove, the route in which dusts and smudges may enter the disk recordingmedium device can be narrowed as much as possible so that dusts andsmudges can be prevented from entering the disk compartment 16effectively.

Moreover, in this embodiment, since the rib 37 (arc-like rib portion 37a and linear rib portion 37 b) is provided on the peripheral edgeportion of the outside opening portion 17 of the lower shell 15, the ribescape groove 70 is provided at the portion opposing a pair of shuttermembers 19 a, 19 b that opposes the rib 37 in the shutter closed stateand the rib 37 and the rib escape groove 70 constitute the dust-proofclearance 71, a dust-proof property obtained when the disk recordingmedium device 10 is preserved in which the opening portions 17, 18 arecompletely closed by the shutter members 19 a, 19 b can be improved andhence dusts and smudges can be effectively prevented from entering thedisk compartment 16.

The cartridge housing can be configured by combining the upper and lowershells without the rotary member. Then, as shown in FIG. 42 which showsan example of the prior art, a cartridge housing may include a shuttermember that can linearly move to open and close an opening portion. Ifthe cartridge housing having such arrangement is provided with thechucking ring 33 and the ring holder 34 of the above-mentionedembodiment, similar effects to those of the above-mentioned embodimentcan be achieved. Further, the opening portion may include only eitherthe upper shell or the lower shell. In such case, the chucking ring maybe provided on a shell having no shell formed thereon.

The present invention has been described so far but the presentinvention is not limited to the above-mentioned embodiment. For example,while the present invention is applied to the example in which theoptical disk is used as the information recording medium as describedabove, the present invention can be applied to magnetic disks such as amagneto-optical disk and a flexible disk and other various kinds ofdisk-like recording mediums. Further, while the present invention isapplied to the example in which the disk recording and reproducingapparatus capable of both of recording and reproducing information isused as the disk recording and/or reproducing apparatus as describedabove, it is needless to say that the present invention may be appliedto a disk recording apparatus or a disk reproducing apparatus that iscapable of either recording or reproducing information.

While the lower shell 15 and the rotary member 14 of the cartridgehousing 12 are provided with the opening portions 17, 18 as describedabove, the present invention is not limited thereto and the upper shell13, for example, may be provided with an opening portion to enable usersto access the disk recording medium device from the upper and lowerdirections of the cartridge housing 12. In this case, theabove-mentioned convex rib and concave groove may be set on the rotarymember and the shutter member. Further, the rotary member and the lowershell may constitute a disk compartment, a disk-like recording mediummay be accommodated within this disk compartment and the upper shell maybe provided with an opening portion. In this case, the above-mentionedchucking ring 33 is provided on the lower shell.

Furthermore, while the shutter opening and closing means is fixed andthe opening portion is opened and closed by moving the disk recordingmedium device when the shutter is opened and closed as described above,the present invention is not limited thereto and the shutter member maybe opened and closed by relatively moving the shutter opening andclosing means and the disk cartridge. For example, the shutter membermay be opened and closed by moving the shutter opening and closing meanswith a suitable means such as a motor after the disk recording mediumdevice has been fixed to the disk loading portion.

As described above, the present invention can be variously modifiedwithout departing from the gist thereof.

INDUSTRIAL APPLICABILITY

As described above, according to the disk cartridge of the presentapplication, in the disk cartridge comprising the cartridge housing(combination of the upper shell and the lower shell or combination ofthe upper shell, the rotary member and the lower shell) including thedisk compartment, the shutter member that is movable between the openingposition and the closing position to open and close the opening portionand the shutter fixing means for holding the shutter member in theclosed state at the closing position, since the shutter member is heldin the opened state by the shutter fixing means even at the openingposition, the shutter member need not be held in the opened state by theopen and hold mechanism of the external apparatus. Thus, there is norisk that vibrations generated from the external apparatus will betransmitted through the open and hold mechanism to the disk cartridgeand the like. Therefore, malfunctions caused by vibrations can beprevented or suppressed when information is written and read. Moreover,even when shocks are applied to the external apparatus, the open andhold mechanism is disengaged from the disk cartridge and the shuttermember can be prevented from being moved to the closed stateautomatically. There is then no risk that the shutter member willcontact with the optical head of the optical pickup device and theturntable. Accordingly, there can be removed a risk that the opticalhead and the shutter member will be broken.

Further, according to the disk recording medium device of the presentapplication, in the disk recording medium device comprising thecartridge housing (combination of the upper shell and the lower shell orcombination of the upper shell, the rotary member and the lower shell)including the disk compartment, the disk-like recording medium, theshutter member that is movable between the opening position and theclosing position to open and close the opening portion and the shutterfixing means for holding the shutter member in the closed state at theclosing position, since the shutter member is held in the opened stateby the shutter fixing means even at the opening position, the shuttermember need not be held in the opened state by the open and holdmechanism of the external apparatus. Thus, there is no risk thatvibrations generated from the external apparatus will be transmittedthrough the open and hold mechanism to the disk cartridge and the like.Therefore, malfunctions caused by vibrations can be prevented orsuppressed when information is written and read. Moreover, even whenshocks are applied to the external apparatus, the open and holdmechanism is disengaged from the disk cartridge and the shutter membercan be prevented from being moved to the closed state automatically.There is then no risk that the shutter member will contact with theoptical head of the optical pickup device and the turntable.Accordingly, there can be removed a risk that the optical head and theshutter member will be broken.

Further, according to the disk recording and/or reproducing apparatus ofthe present application, in the disk recording and reproducing apparatuscomprising the disk recording medium device including the diskcompartment in which the disk-like recording medium is accommodated andthe shutter member movable between the opening position at which itopens the opening portion formed so as to expose a part of the disk-likerecording medium and the closing position at which it closes the openingportion, the shutter opening and closing means for opening and closingthe shutter member and the table drive apparatus for chucking androtating the disk-like recording medium, since the shutter member isheld in the opened state by the shutter fixing means even at the openingposition, the shutter member need not be held in the opened state by theopen and hold mechanism of the external apparatus. Thus, there is norisk that vibrations generated from the external apparatus will betransmitted through the open and hold mechanism to the disk cartridgeand the like. Therefore, malfunctions caused by vibrations can beprevented or suppressed when information is written and read. Moreover,even when shocks are applied to the external apparatus, the open andhold mechanism is disengaged from the disk cartridge and the shuttermember can be prevented from being moved to the closed stateautomatically. There is then no risk that the shutter member willcontact with the optical head of the optical pickup device and theturntable. Accordingly, there can be removed a risk that the opticalhead and the shutter member will be broken. Therefore, the informationsignal is recorded and reproduced by using the disk recording mediumdevice in which the optical head and the shutter member can be preventedfrom being broken. Thus, reading and writing of information can benormally executed in safety.

1. In a disk cartridge comprising: a cartridge housing in which a diskcompartment is formed between an upper shell and a rotary member orbetween said rotary member and a lower shell by combining said uppershell, said rotary member and said lower shell, said rotary member issupported by at least one of said upper shell and said lower shell so asto become freely rotatable and in which an opening portion is providedon at least one of said upper shell and said lower shell or on at leastone of said upper shell and said lower shell and said rotary member; ashutter member provided on said cartridge housing so as to becomemovable between the opening position at which it opens said openingportion and the closing position at which it closes said opening portionin response to rotation of said rotary member; and shutter fixing meansfor holding said shutter member in the closed state at said closingposition, a disk cartridge characterized in that said shutter member isheld in the opened state at said opening position by said shutter fixingmeans.